Sometimes on Saturday nights, during my dinner break from work, I play poker at a friend’s house. It’s a small stakes dealer’s choice game and I usually play for roughly 90 minutes and I tend to win a small amount of money. (tonight, it was $17)
Generaly speaking, are the odds of winning money at this game decreased by playing longer or does it matter?
If you assume all players are of equal skill and luck is the only difference, then playing longer tends to result in things evening out. But the difference may not be luck - you may be a better player than the others. If so, playing longer will tend to leave you with more money.
Not with poker generally speaking. There isn’t a built in house advantage so you can play all you want. It is just your skill level that determines your winnings over the long term.
With most casino games however, the longer you play, the more you are at a disadvantage. Every round, trial, or pull has a built in house advantage so the more of those you go through, the worse off you are. Everyone is virtually guarenteed to lose at casino games over the long-term barring hitting some mega-jackpot. It is possible to win in the short-term but not in the long-term (barring nearly impossible difficult card counting in Black Jack)
What most people don’t realize is that the laws of probability don’t stop when you call it quits at the casino after a few hours. They never reset and are there for life. The sum of every game that you ever play should be looked at as one big game. That means that short-term wins are really just temporary blips in a larger game that you will lose if you stick to games that have a negative expectation of winnings.
When dealing with games of chance, there are two things to consider: the Expected Value (EV) and the Standard Deviation (SD).
EV is what you expect to gain or lose every time you put down a bet. At a casino, typically your EV is negative - you expect to lose money. If you’re playing poker with friends who are exactly the same skill level as you, your EV is 0. If you’re better than your friends, your EV is positive.
SD is how a measure of how often your actual result will come close to your EV. For example, if you flip a coin (heads you lose $1, tails you gain $1), your EV is zero and your SD is small. The same game, with higher stakes (heads you lose $1,000,000, tails you gain $1,000,000) has the same EV, but a much larger SD.
When you play poker with friends, your EV will not change based on the time you spend playing. But your SD will. If you are slightly better than your friends, the odds of you winning money in the long run is absolutely enormous. It’s highly unlikely you’ll win a ton of money, and highly unlikely you’ll lose money. In the short run, however, you’re more likely to lose money, and more likely to gain a lot of money.