One time through method for smaller bankrolls. With this method you put your bankroll through a single machine one time. However, you don't play any credits won. You take those and move on, or go home. This can work pretty well, but if you hit a few cold machines in a row your day may be over quicker than you planned.

A better variation on the above method is to break your bankroll down into $20 or so increments. You only put one increment through a machine. If it does pretty well play another increment. If not, move on. But again, try to resist playing the credits that you win. Or at least put a portion of them back.

Our preferred method. If you sit and play any machine long enough you'll run into a winning streak of some sort, that is if you don't end up broke first. A better approach is to limit what you're going to play in any one machine unless it is hitting. If you reach that limit, move on to another machine and try it.
For example, we'll try to spend no more than what it takes for 10-15 spins with maximum coins. If we hit nothing we move on. By 'nothing' we mean not even a cherry, mixed bars, or single wild symbol. We don't count getting our coins returned for three blanks as a hit, it's just a free spin. If we do hit we may stay for another ten spins or so but it depends on what we hit in those ten spins and also what our gut feel is. Don't discount your instinct. In any event we don't replay all of our winnings.

A variation on our preferred method is use to only one coin for the 10-15 spin test.
If it hits well enough we move up to maximum coins and keep playing. However, our experience is that this sometimes costs us a considerable win.
If during the test spins we hit something big we are awarded less credits than if we had played the max.
If we move up to the maximum coins and keep playing but find that the big win was just a fluke on that machine, we can easily lose as much or more than we had won.
If we had played max coins during the test we would be further ahead. For example, if we play one coin for 10 spins on a 3 coin machine and hit triple bars for a 30 credit win we may then move up to 3 coin play. But if we don't hit anything in the next 10 spins we quit and we're down 10 coins (30 won - 10 for the test - 30 played at the max).
However, if we had played the max for the test the triple bars would have given us a 90 credit win and we would be 30 credits up (90 won - 30 for the test - 30 played after the win). Of course, given how today's slot machines work we may not have hit the triple bars if we had played three coins. It would have taken a millisecond or two longer to drop the coins and so we would likely have missed that spin.
So this still may be a good alternative method, especially if your bankroll isn't as much you'd like. If you find a hot machine with this method you may still end up taking home some money.

OK, so now you have a hot machine. You've put your bankroll through it and have several hundred credits built up. When do you quit? Ideally as soon as the bankroll is gone. Cash out and take your winnings home for the next trip.
Realistically, you need to at least set a limit that you will not go below. If you are ahead you want to stay that way. If you're not you should quit that machine right away (and probably should have earlier).
A method we sometimes use is to try to stay ahead no less than 20-25% of the original money we put into the machine. If we play $40 through a quarter machine (that's 160 credits) we might play down to 200 credits, but no less. But even if we're a lot farther ahead than that, if things turn cold (no hits in 10-20 spins) we quit. At that point we at least try to put back what we're ahead and if we keep playing we stick to our original bankroll. If we don't, we usually go home saying to each other, "we should have quit when we had those four buckets full," or something like.
Sound familiar? Try to stick to playing only your original bankroll and try not to replay the credits you win.

If you find that things aren't going as well as you hoped but you're not ready to quit, consider moving down in denomination. If you've been playing 3 coin dollar machines try 2 coin machines or move down to 3 or 5 coin quarter machines.
If you've been playing quarters, consider trying a nickel machine. You'll extend your play without going over your original bankroll. However, be careful about going the other way! If you set out to play quarters and you start winning, stick with quarters and go home a winner. Plan your next trip to play dollars.
You have to have a money management technique and stick to it if you want to go home with money on most trips. If you find yourself more often than not going home with nothing to show for the bankroll you spent, you need to rethink how you're managing your money and play.

How much of a bankroll do you need? We'll give you the general rule of thumb that we try to work with. You may adjust it up or down depending on your financial situation and comfort level.
We like to use the ten-spin method explained above to find a good machine. We'd like to be able to try at least 15-20 machines. If we know we're likely to play mostly 3 coin machines that means we need 450-600 coins (3 coins X 10 spins X 20 machines).
So if we're playing quarters we like to take around $150 per player. For dollar machines that would be $600. For nickel machines $30. We time our trips based on when we are able to afford these levels.

Whatever you decide to take as your bankroll the most important principle is to not go over it. Once you get into that habit you'll soon be calling 1-800-BETSOFF.
Take your stake in cash and if possible leave your credit cards, check book, and ATM cards at home, in your room or in the hotel safe. If you have to leave the casino to get them you'll be more likely to re-think the situation. This is difficult to do when you're traveling.
But you can still set a time limit for yourself. Once that time is up, take a break outside of the casino and re-think your strategy. Is it time to quit for the day? Are you ahead or down? Have you eaten in the last eight hours?