10 Rookie Gambling Mistakes You Might Be Making

Are you new to gambling?

If so, you’re probably making the same common mistakes that most other rookies make. There’s nothing wrong with that at this stage in your gambling career or hobby.

If you don’t start learning why these are mistakes, though, you could be in for a rough time in the future.

The purpose of this post is to point out 10 rookie gambling mistakes you might be making so that you can do something else instead.

1 – Trusting Your Hunches

Some people believe in their hunches and act accordingly. This isn’t always a mistake, because sometimes it’s irrelevant. Other times, acting on your hunches can (and will) cost you money.

Here’s an example:

You have a hunch that red is going to come up on the next spin of the roulette wheel, so you bet on it instead of black.

A bet on red has just as good a chance of winning as a bet on black, so this isn’t a mistake. Either bet has a 47.37% probability of winning.

But here’s another example:

You’re playing blackjack, and you have a hard total of 15. The dealer has a 5 showing. You have a hunch that the next card in the deck is either a 5 or 6—it’s just a hunch.

So you hit.

This is a big mistake. In this situation, you should stand because the dealer has a good chance of busting a stiff hand here. (The dealer must hit any total of 16 or less regardless of what your total is.)

As long as you don’t bust, you have a good chance of winning this hand.

Basic strategy and the math behind it always trumps your gut feelings or hunches.

Players who ignore basic strategy and just bet their hunches lose another 2% or 3% to the casino from each bet than players who stick with basic strategy regardless of their hunches.

2 – Gambling with Money You Don’t Have

At first glance, it might seem impossible to gamble with money you don’t have.

But this might be the biggest mistake most gamblers make.

You should never gamble with any money you can’t afford to lose. This means that if you’re behind on the rent or your child support payments, you should not be gambling that money. You should pay off your debts first.

Gambling is an entertainment expense. You should spend on entertainment only after your other obligations in life are already fulfilled. This includes delinquent bills.

Some people even gamble with money they need urgently to pay the mortgage or the rent. They figure they’re bound to at least break even, so they’ll be fine.

People like this sometimes wind up homeless and living in the streets. I’m not saying that to judge them or ridicule them. I’m just stating a fact and hoping that you’ll learn from their examples.

Never gamble with money you can’t afford to lose or with money you don’t really have.

3- Not Taking Care of Yourself

It’s easy to make big mistakes (like betting money you can’t afford to lose) if you’re exhausted or drunk. That’s why you should make an effort to get enough sleep and stay away from alcohol.

In fact, anything you do that’s bad for your health affects your ability to make prudent decisions. Making bad decisions is how you lose money gambling.

A healthy mind resides in a healthy body. If you’re overweight and under-conditioned, lose some weight and start exercising. Eat more fruits and vegetables, and take a multivitamin.

Stop eating so much junk food.

These all seem like they’re only tangentially related to your gambling experience, and maybe that’s so. But just because the relationship is only tangential doesn’t mean it’s not important.

The more effort you put into keeping yourself healthy and capable of good decision-making, the more likely you are to succeed gambling.

4 – Using Betting Systems

Using a betting system is only a mistake if you overestimate what that betting system might accomplish for you. As long as you understand that betting systems don’t change the overall math behind the game, and that they won’t make you a winner in the long run, using betting systems is fine.

A betting system is just a systematic method of raising and/or lowering your bets based on what happened on your previous wagers. Some people think this can increase your probability of winning, but they’re wrong.

Think of a bet as a negative number. No matter how much you raise or lower that number, it’s still negative. And when you add a series of negative numbers together, you get a negative number. There’s no way to get that sum to equal a positive number.

The most common example is the “doubling-up” system, or the Martingale. With this system, you double the size of a bet every time you lose. This recoups your previous losses and leaves you with a one-unit profit.

Here’s an example of the doubling-up system in action:

You bet $10 on red at the roulette table and lose. On your next bet, you wager $20, but you lose again. Now you double up again, betting $40, and you lose AGAIN.

On your 4th bet, you wager $80 and win.

Since you lose $70 on your previous 3 bets, you’re left with a $10 profit when you win that 4th bet.

The system ignores the fact that long losing streaks happen occasionally—often enough, in fact, that they’ll break the system.

This is because of 2 factors:

  1. Your finite bankroll
  2. The casino’s betting limits

Most people don’t have an unlimited bankroll. $10 might not be a lot of money to most people, but if you lose 7 times in a row, you’rehaving to bet over $1000 to catch up. That’s a lot of money for most $10 bettors.

The other problem is that casinos cap the amount you can bet on a game like roulette. Most casinos don’t accept bets of more than $500 at the roulette table, which means that even if you have an almost infinite bankroll, the casino won’t let you bet enough to catch up and profit anyway.

Just using a betting system isn’t by itself a mistake.

Thinking that it will change the odds in your favor is the mistake.

You can use a betting system if you think it’s a fun way to play, just as long as you understand that, in the long run, you’re still playing at a disadvantage against the house.

5 – Playing Slot Machines

No game in the casino will decimate your bankroll as quickly as a slot machine. They seem so innocuous, and everyone plays them, and in some cases, you can even play for pennies.

But penny slot machines always cost more than a penny per spin.

And that air of being innocuous is just an illusion.

The reason playing slot machines is a mistake is because of the amount of money you’ll lose playing, especially when compared with other games that are as much fun or more fun.

Part of the reason slot machines are so profitable for the casino is the rate at which you’re able to play. In a game of blackjack, you might get 200 hands per hour in—IF you’re the only player at the table and trying to play fast.

On a slot machine, you’ll probably average 600 bets per hour—900 if you’re really fast.

That’s 1 of 3 factors that determine how much money you’re mathematically expected to lose per hour—the number of bets you’re making per hour.

The other 2 factors are your average bet size and the house edge.

In blackjack, if you play with perfect basic strategy, the house edge might be as low as 0.5%, but let’s say that it’s an average game with less than ideal rules, and you’re only at 1%.

On a pretty good slot machine in Vegas, the house edge might be as low as 8%.

Now you multiply the average bet by those 2 factors. Let’s say you’re playing blackjack for $5 per hand—you’re a low roller.

That means your predicted hourly loss at the blackjack table is 200 X $5 X 1%, or $10/hour.

On the other hand, you’re playing a slot machine where your minimum bet is 75 cents per spin.

Your predicted hourly loss on that slot machine is 600 X $0.75 X 8%, or $36/hour.

And keep in mind, you’re betting 80%+ less per bet on the slot machine than you are on the blackjack table.

Even roulette offers you a lower hourly cost, and the house edge for roulette is 5.26%.

45 spins per hour X $5 per spin X 5.26% = $11.84 per hour in predicted losses.

If you just love sitting in front of a gambling machine, try video poker instead. The house edge on many video poker games is lower than 5%. If you learn how to recognize the right pay tables and learn how to play with close to optimal strategy, you can get that number to less than 1%.

6 – Taking Insurance in Blackjack

Insurance in blackjack is a side bet that the dealer has a 2-card total of 21. It seems like a no-lose proposition. You only put up half of your initial bet, and if the dealer has a blackjack, you win 2 to 1 on the insurance bet. This “cancels out” the loss on your initial bet. (A dealer blackjack always wins unless you also have a blackjack.)

Mathematically, though, the right way to look at insurance is as a completely separate bet and decide whether it’s a positive expectation bet or not.

You only get to take insurance when the dealer’s face-up card is an ace. This means the insurance bet pays off if the dealer’s face-down card is a 10.

What’s the probability of winning the bet, then?

You have 52 cards in the deck, and of those, 16 are worth 10 points.

This makes the probability of the dealer having a 10 as her face card 16/52, or 30.77%. We’ll round that up to 31% for purposes of examining whether the bet is a positive expectation bet or not.

Now assume you make this bet 100 times for $100 each, and you get mathematically perfect results.

You’ll win $200 on 31 of those bets, for total winnings of $6200.

You’ll lose $100 on 69 of those bets, for total losses of $6900.

This results in a net loss of $700 over 100 hands, or an average loss of $7 for every $100 you bet.

That’s a house edge of 7% for this bet.

In a game where the house edge overall is less than 1%, placing a bet where the house has an edge of 7% is foolhardy at best.

Taking insurance is always a mistake unless you’re counting cards and the deck is rich in 10s.

Even then it’s a mistake, because it’s a tip-off to the casino that you’re counting cards.

7 – Taking Almost Any Other Side Bet in the Casino

Insurance isn’t the only side bet in the casino. It’s just the most common. One thing that side bets in the casino seem to have in common is lousy odds.

Different variations of blackjack offer different side bets. They almost always carry an absurdly high house edge. Here are a couple of examples:

21 + 3 is a side bet that pays off based on your 2 cards combined with the dealer’s face-up card. If those 3 cards form one of the following poker hands, the side bet pays off:

  1. A flush
  2. A straight
  3. A 3 of a kind

The most basic version of this side bet offers a payout of 9 to 1 if you hit any of those hands.

The house edge on that bet is 3.24%.

That’s not terrible when compared to many other casino games. After all, roulette has a house edge of 5.26%.

But compared to the less than 1% you should expect at blackjack, it’s pretty bad.

Another common blackjack side bet is called “super sevens.” You’re betting that your hand will have a lot of 7s in it. The payout depends on how many 7s you wind up with and what the suits of those 7s are.

If you get a 7 as your 1st card, the payoff is 3 to 1.

If you get 7s on both your 1st 2 cards, the payoff depends on whether they’re of the same suit. Unsuited 7s are worth 50 to 1, and suited 7s are worth 100 to 1.

If you get 7s on your 1st 3 cards, the payoff is 500 to 1 if they’re unsuited, but it’s 5000 to 1 if they’re suited.

With big payoffs like these, you might think the house edge on this bet is low.

You’d be mistaken, though.

The house edge for this bet is at least 11.4%, but it’s probably more like 12.6%. The difference is based on whether you get a 3rd card if the dealer has a blackjack. If you do, you see the 11.4% edge.

That difference of 1.2% does little to make this into anything other than a lousy bet.

8 – Gambling Online at a Rogue Casino

Most people in the United States have various opinions about whether playing at an online casino is legal. (It is.)

What’s illegal is running an online casino.

As a result, the companies running online casinos are located offshore and keep most of the details about their ownership and management a secret.

This doesn’t mean that all these businesses are crooked.

It does mean that your probability of running into a crooked business are higher.

Does this mean you should avoid gambling online?

Not really.

You just need to do enough research to find a casino with a good reputation. In fact, you don’t even have to worry about most online casinos cheating you at their games. They let the house edge handle that, in most cases.

The biggest, most common problem most people who have problems with online casinos run into is failure to pay winnings. Sometimes the casino just slow pays the winnings.

It’s easy enough to find lists of online casinos to avoid, though.

And it’s easy to find reputable online casinos, too. Just look for a gambling information site you trust—hopefully this one—and look for their recommendations.

Most gambling information webmasters try to direct their readers to reputable companies. The sites they recommend reflect on them, and most of them know it.

If you do have a dispute with an online casino, you can ask the webmaster of the site that referred you to intercede on your behalf, too.

9 – Bluffing a Lot

If you play poker and don’t know what you’re doing, you might be bluffing too often. This is a common rookie poker mistake. Here’s why:

Most poker rookies play for low stakes. The players at this level are often too bad at poker to fold. If you’re at a table with a player who never folds, bluffing is pointless. You have a 0% chance of taking down a pot by bluffing.

Even if the players at your table are good enough to fold, you should only bluff against one or 2 opponents. The probability of winning the hand changes dramatically with more opponents to bluff.

Just to keep the math simple, let’s assume that you’re heads-up with a player who you estimate will fold in the face of your bluff 50% of the time. As long as you’re winning better than even money from the pot, this bluff is a positive expectation move.

Now let’s assume you face 2 players, each of whom has a 50% chance of folding in the face of your naked aggression. You only take down this pot if they both fold, which will happen only 25% of the time. (50% X 50% = 25%).

This is 1 out of 4 times, so you need 3 to 1 pot odds for this to be profitable. Sometimes there’s that much money in the pot. Sometimes there’s not.

Now assume you face 3 players who all have that same folding probability. Now you only have a 12.5% probability of taking down the pot. (50% X 50% X 50%).

That’s a 1 in 8 chance, so you need at least 7 to 1 pot odds to make this profitable.

It’s rare that you’d have that much money in the pot with only 3 opponents.

If you watch poker on television or in the movies a lot, I can forgive you for thinking that the game is all about bluffing. It is partially about bluffing, but it’s about a lot more than that. Bluffing is often the worst play you can make.

I had a caller on a radio station ask me once for advice on how to do well in that night’s freeroll on PokerStars. My advice was simple:

Don’t bluff.

10 – Betting on Your Favorite Team

When you’re serious about betting on sports, you need to set aside your status as a fan of a certain team and bet based on the expected value of the bet. Sometimes this will mean betting against your favorite team.

I have a friend who LOVES the Dallas Cowboys. He literally places a $100 bet on the Cowboys every week. He almost always has a losing season.

The book sets the point spread in such a way that my friend has a roughly 50% probability of winning that bet every week.

But they also require him to risk $110 to win $100.

So my friend loses $110 half the time, and wins $100 the other half.

That’s a losing proposition over time.

If my friend were smart, he’d look for opportunities to bet where the book has a point spread set that’s inaccurate in one direction or the other.

Then he’d only bet those opportunities, regardless of who the Cowboys are playing. Some weeks he might not even bet on the Cowboys game at all, while other weeks, he might bet against them. He might even get to bet on them to win once in a while, but his love of the team wouldn’t be a deciding factor in how he bets.


Rookies in the gambling world tend to make the same mistakes repeatedly. Some of these are general gambling mistakes, like playing with money you can’t afford to lose. Some of these are game-specific, like taking insurance in blackjack.

In any case, you can avoid the most common gambling mistakes easily enough.

Which gambling mistakes are you guilty of, and do you plan to change what you’re doing after reading this post?

Michael Stevens

Michael Stevens has been researching and writing topics involving the gambling industry for well over a decade now and is considered an expert on all things casino and sports betting. Michael has been writing for GamblingSites.org since early 2016.

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