Until a few years ago, players interested in learning poker would start out by playing in fixed-limit games. Most casinos and card rooms only offered Limit Hold 'em or Limit Stud, so players had to get used to the dynamics of structured betting. But now, many players are jumping directly into No-Limit. There's nothing wrong with this approach, but lately, I've seen a lot of players at the Limit tables who are applying big-bet principles to fixed-limit games. They're making big mistakes that reflect their inexperience with limit betting.
In No-Limit, the biggest mistake you can make is putting money in a pot when drawing dead or very slim. Usually, by the turn or river, you'll face large bets that threaten your entire stack, so calling on a second-best hand is a huge error. In Limit Hold 'em, however, the biggest mistake you can make is folding the best hand on the river. By the river in Limit Hold 'em, you're often getting odds of 9, 10, or 11 to 1 to make a call. Given these odds, it's often proper to call on the river with some very modest holdings, even if there's only a small chance that you can pick off a bluff and win the pot at showdown.
For example, say you're playing in a short-handed Limit Hold 'em game and you raise on the button with As-7s. A very aggressive opponent in the big blind calls. The flop comes Jd-8d-7c, giving you bottom pair. The big blind checks, you bet, and are check-raised. On this board, there are a variety of straight draws and flush draws. An aggressive opponent could be raising on any number of hands, so you'd need to call this raise or even consider three-betting.
If the turn brings a scary card, say the Td, you can fold, as there are very few hands you can now beat. However, if the turn is a blank, like the 2c, you're probably going to be in a position where you'd need to call your opponent down. Third pair isn't much, but it will win at showdown enough of the time to make the call worthwhile.
In No-Limit, you'd probably want to fold if you were check-raised while holding bottom pair. It would cost too much to figure out whether or not you were ahead. But in Limit, your total liability in the hand is only two more big bets, making the call worthwhile.
The other major error I see from No-Limit players who move to Limit is that they fail to play enough hands from the big blind. In a recent tip, Jennifer Harman discussed big blind play in Limit Hold 'em in some detail. She suggested playing a lot of hands from the big blind, including any two cards that can make a straight. Jennifer's an expert player, and you might be better off being a little more selective than she is. But still, you should be playing a lot more hands from the blinds in Limit than you would in No-Limit.
Think of it in terms of odds. In a Limit game, you'll be getting 3.5 to 1 to call a single raise from the big blind (two small bets from the raiser, your big blind, and the small blind). Plus, in many games, you can count on the pre-flop raiser to follow up with a bet on the flop, whether he hit or not. That gives you odds of 4.5 to 1. If the raiser is an aggressive player in late position, you can't give him credit for much of hand to start with, so, even a hand like 5-6 off-suit is often good enough to play from the big blind.
In No-Limit, you probably want to fold the same hand and wait for a better spot. But this is the type of adaptation you'll need to make if you want to master all forms of poker, including Limit and No-Limit. If you're moving from No-Limit poker to Limit, keep in mind that you're going to be calling opponents down more often and that you're going to want to play many more hands from the big blind.