In no limit Texas holdem play; I am always concerned about players from early position who limp into the pot. In my experience, there are two kinds of hands that do this, assuming that the player in question is an average player or better.
The first type of hand is a drawing hand that has a chance to make a big hand on the flop, like medium or small pairs, hoping to hit a set. The other type is a big hand like Aces or Kings, hoping for a raise behind them so they can push all in before the flop.
Because of this, if I decide to play a hand behind an early limper, I almost always raise when I enter the pot. I want to find out before I get too involved how much they like their hand. If they push all in after my raise, I tend to fold all but my very best hands. Of course, I do tighten up quite a bit on my starting hand requirements in this position, unless the player is particularly poor. Then I will play the hand as normal. If the early position limper is an above average player, I will fold hands as good as AQs at times.
The important points are that you need to have a solid idea of the strength of your opponent, the range of hands he or she will limp with and your ability to outplay them after the flop. The rule I follow the majority of the time is when an early limper moves all in after a raise, I assume they have at worst AK, until they prove otherwise. This move is a clear sign of strength in most games I play in.
For this reason, I will limp in behind with a few hands that have a chance to do well on the flop, like medium pairs. Many players who think they are playing correctly will limp with a big hand hoping for a raise, and move all in on the flop or turn when the pot isn’t raised pre flop. Against these players, when I am able to hit a set I have an excellent chance to double up. When I hit a set on the flop and it is checked to me, I always bet in this situation to give them a chance to move all in.
Like many situations, if you have any doubts, your best bet is to fold before the flop. In no limit play, you only have to win a few big hands per session to make money, and there will be another hand in just a few minutes. There is no need to get involved when you don’t have the best chance to win. Until next week, good luck at the tables!