Slot machines, and increasingly video poker machines, are the most popular forms of gaming in casinos. Some table players look down on slots because they are pre-programmed with a payback percentage and a hit frequency, thinking that this means slots are not true gambling. However, in a sense the casinos have similarly set the payback percentages of table games through the various rules they've established for the games. While I am primarily a table player, I enjoy an occasional slot session. There have even been nights when the slots were the only way I was able to win anything.
Slot machines contain a "random number generator" (RNG) micro-computer that constantly (even while the machine is not being used) spits out numbers. These random numbers correspond to positions on each of the reels in the machine. When you pull the handle or push the "Spin" button you aren't really initiating anything except the spinning of the reels which is merely for show. You are simply telling the machine to display the reel positions that correspond to the last set of random numbers that were generated.
The above is important because it de-bunks some long-held assumptions about slot machines. Like the roulette wheel, where every play is completely random and independent, one pull of a slot handle is completely random and completely independent of the previous or next pull. It all comes down to the precise moment that you pull that handle or push that "Spin" button (i.e. which set of random numbers you select). Pulling the handle or pushing the button a 100th of a second later would yield a totally different result.
The result of the above is this:
Lets take a simplified example of a three-reel machine. If a machine has 10 symbols on each reel, and there are two "blank" positions between each symbol, that's 30 positions on each reel. A three-reel machine gives 303 or 27,000 possible results that you could get when you pull the handle or press the "Spin" button. A fair number of these possible results will give smaller, partial payouts, but there's only a 1 in 27,000 chance that the combination of numbers that represents the machine's jackpot will be generated. Because the random numbers are generated so frequently and so rapidly, the combination of numbers that correspond to this 1 in 27,000 jackpot position of the reels could be generated quite frequently (relatively speaking). It's the probability that you will pull the handle or hit the "Spin" button at the precise moment that they are generated is what is very low.
Given the random number generation, luck is as involved with slot play as it is with table play. However, the key point with slot machines is that they are set up with different payback percentages and hit frequencies. (The odds at table games are pretty much the same wherever you play because the rules are consistent from one casino to the next.) Machines that pay off frequently are said to be "loose". But loose isn't always a good thing if you're looking for a hefty jackpot. If a machine is has a high payback percentage (98%), but also has a high hit frequency, you'll end up with a lot of little payouts. You may come out ahead, but you'll be less likely to hit a sizable payoff that's worth writing home about. The best machines are those with a high payback percentage and a lower hit frequency.
So how do you spot these machines? You can't. The best you can do is ask a slot attendant or change attendant which machines are loose and hope Lady Luck is with you. And don't blame the attendant for giving you a bum steer if you come up dry. They have no control over those RNGs in the machines and given that the hit frequency is calculated over the long term, a machine could have a loose period but then tighten up. In addition, the casino can (and routinely do) change the payback percentages and hit frequencies of machines from a central control computer. If you do win a sizable sum based on the assistance of a slot or change attendant, a tip would be a nice gesture.
If the casinos are going to reduce their take on a machine (in the form of a higher payback percentage) you can bet they want to get some bang for their bucks. They will usually disperse their looser machines in areas that are visible by the largest number of people. You're more likely to find a loose machine near the front desk where arriving players are standing in line watching the action, near "the cage", on main aisles, or are visible from buffet and show lines or lounges. Note that I said "visible from" and not "next to". People who are stuck in long buffet and show lines are a captive audience who are likely to play machines next to them simply to kill time while they wait. You typically won't find loose machines in areas where people stand idle.
You will often see signs that say "Up to 98% payback" indicating that they have loose machines. This means that over the long term the slot will pay out 98 cents of every dollar that is played. The "up to" is the key point here. It means that a casino could have only one machine set to pay back at 98% to comply with the sign. If you find an area of slots with a sign without the "up to" you may want to give it a try.
A machine with a 98% payback give the house a 2% edge, which is comparable with craps and blackjack. However, there are very few machines in a casino that have this high of a payback percentage. The worst machines can be as low as 75% (giving the house a whopping 25% advantage).
The hit frequency is set to pay out smaller amounts occasionally to keep the person playing the machine. A lot of people will think they're "winning" if they get any money at all out of a slot machine. But if you put $20 into a machine and you get $15 back you've lost $5. I have an aunt who will gladly tell you how much she "won" playing the slots, but when you ask her how much she put into the machines to get those "winnings" she clams up. The casinos just love these kind of people.
Have a strategy for both playing the slots and managing your money. You can refine a strategy for yourself based on some well-known practices:
Personally, I've had decent results with dollar machines at the Riviera and Circus Circus. That may not be just a coincidence. The older places near the north end of the Strip may set their machines looser to try and draw players away from the newer, fancier resorts. If you're not having any luck on the Strip, try hopping one of the free shuttles to one of the off-Strip casinos.
While I have no way of proving it, it seems like the slots tighten up on Friday mornings and stay that way through the weekend (to make more money off of the crowds that drive in). If you stay includes weekdays, play the slots then and switch to table games on the weekends.
Occasionally playing slots is fun, but if that's all you play you are really short-changing yourself. It's like eating toast for dinner day after day after day. Playing table games will greatly enhance your casino experience and they're not as hard as they look. Back on the Gaming page you'll find links to tutorials for craps, roulette and blackjack. Give them a try!