The most popular slots are penny and nickel video games along with quarter and dollar reel-spinning games, though there are video games in 2-cent, 10-cent, quarter, and dollar denominations and reel spinners up to $100. Most reel spinners take up to two or three coins at a time while video slots can take 45, 90, and even 500 credits at a time.
Nearly all slot machines are fitted with currency acceptors -- slide a bill into the slot, and the equivalent amount of credits is displayed on a meter. On reel-spinning slots, push a button marked "play one credit" until you've reached the number of coins you wish to play. Then hit the "spin reels" button, or pull the handle on those few slots that still have handles, or hit a button marked "play max credits," which will play the maximum coins allowed on that machine.
On video slots, push one button for the number of paylines you want to activate, and a second button for the number of credits wagered per line. One common configuration has nine paylines on which you can bet 1 to 5 credits. Video slots are also available with 5, 15, 20, 25, even 50 paylines, accepting up to 25 coins per line.
Many reel-spinning machines have a single payout line painted across the center of the glass in front of the reels. Others have three payout lines, even five payout lines, each corresponding to a coin played. The symbols that stop on a payout line determine whether a player wins. A common set of symbols might be cherries, bars, double bars (two bars stacked atop one another), triple bars, and sevens.
A single cherry on the payout line, for example, might pay back two coins; the player might get 10 coins for three of any bars (a mixture of bars, double bars, and triple bars), 30 for three single bars, 60 for three double bars, 120 for three triple bars, and the jackpot for three sevens. However, many of the stops on each reel will be blanks, and a combination that includes blanks pays nothing. Likewise, a seven is not any bar, so a combination such as bar-seven-double bar pays nothing.
Video slots typically have representations of five reels spinning on a video screen. Paylines not only run straight across the reels but also run in V's, upside down V's, and zigs and zags across the screen. Nearly all have at least five paylines, and most have more -- up to 50 lines by the mid-2000s.
In addition, video slots usually feature bonus rounds and "scatter pays." Designated symbols trigger a scatter pay if two, three, or more of them appear on the screen, even if they're not on the same payline.
Similarly, special symbols will trigger a bonus event. The bonus may take the form of a number of free spins, or the player may be presented with a "second screen" bonus. An example of a second screen bonus comes in the long-popular WMS Gaming Slot "Jackpot Party." If three Party noisemakers appear on the video reels, the reels are replaced on the screen with a grid of packages in gift wrapping. The player touches the screen to open a package and collects a bonus payout. He or she may keep touching packages for more bonuses until one package finally reveals a "pooper," which ends the round. The popularity of such bonus rounds is why video slots have become the fastest growing casino game of the last decade.
When you hit a winning combination, winnings will be added to the credit meter. If you wish to collect the coins showing on the meter, hit the button marked "Cash Out," and on most machines, a bar-coded ticket will be printed out that can be redeemed for cash. In a few older machines, coins still drop into a tray.
Many slot players pump money into two or more adjacent machines at a time, but if the casino is crowded and others are having difficulty finding places to play, limit yourself to one machine. As a practical matter, even in a light crowd, it's wise not to play more machines than you can watch over easily. Play too many and you could find yourself in the situation faced by the woman who was working up and down a row of six slots. She was dropping coins into machine number six while number one, on the aisle, was paying a jackpot. There was nothing she could do as a passerby scooped a handful of coins out of the first tray.
Sometimes players taking a break for the rest room will tip a chair against the machine, leave a coat on the chair, or leave some other sign that they'll be back. Take heed of these signs. A nasty confrontation could follow if you play a machine that has already been thus staked out.
Payout percentages have risen since the casinos figured out it's more profitable to hold 5 percent of a dollar than 8 percent of a quarter or 10 percent of a nickel. In most of the country, slot players can figure on about a 93 percent payout percentage, though payouts in Nevada run higher. Las Vegas casinos usually offer the highest average payouts of all -- better than 95 percent. Keep in mind that these are long-term averages that will hold up over a sample of 100,000 to 300,000 pulls.
In the short term, anything can happen. It's not unusual to go 20 or 50 or more pulls without a single payout on a reel-spinning slot, though payouts are more frequent on video slots. Nor is it unusual for a machine to pay back 150 percent or more for several dozen pulls. But in the long run, the programmed percentages will hold up.
The change in slots has come in the computer age, with the development of the microprocessor. Earlier slot machines were mechanical, and if you knew the number of stops -- symbols or blank spaces that could stop on the payout line--on each reel, you could calculate the odds on hitting the top jackpot. If a machine had three reels, each with ten stops, and one symbol on each reel was for the jackpot, then three jackpot symbols would line up, on the average, once every 10310310 pulls, or 1,000 pulls.
On those machines, the big payoffs were $50 or $100--nothing like the big numbers slot players expect today. On systems that electronically link machines in several casinos, progressive jackpots reach millions of dollars.
The microprocessors driving today's machines are programmed with random-number generators that govern winning combinations. It no longer matters how many stops are on each reel. If we fitted that old three-reel, ten-stop machine with a microprocessor, we could put ten jackpot symbols on the first reel, ten on the second, and nine on the third, and still program the random-number generator so that three jackpot symbols lined up only once every 1,000 times, or 10,000 times. And on video slots, reel strips can be programmed to be as long as needed to make the odds of the game hit at a desired percentage. They are not constrained by a physical reel.
Each possible combination is assigned a number, or numbers. When the random-number generator receives a signal -- anything from a coin being dropped in to the handle being pulled -- it sets a number, and the reels stop on the corresponding combination.
Between signals, the random-number generator operates continuously, running through dozens of numbers per second. This has two practical effects for slot players. First, if you leave a machine, then see someone else hit a jackpot shortly thereafter, don't fret. To hit the same jackpot, you would have needed the same split-second timing as the winner. The odds are overwhelming that if you had stayed at the machine, you would not have hit the same combination.
Second, because the combinations are random, or as close to random as is possible to set the program, the odds of hitting any particular combination are the same on every pull. If a machine is programmed to pay out its top jackpot, on the average, once every 10,000 pulls, your chances of hitting it are one in 10,000 on any given pull. If you've been standing there for days and have played 10,000 times, the odds on the next pull will still be one in 10,000. Those odds are long-term averages. In the short term, the machine could go 100,000 pulls without letting loose of the big one, or it could pay it out twice in a row.