[Lloyd]

There are three factors to consider when calling a raise like this. First, how many people are in the pot? If you're heads up and have some chip you can easily call this (or re-steal if you think that'll work). Second, in a multi-way pot as others have said, are you closing the action? If not, there's certainly more risk to playing but if the initial limper has been very loose maybe you call anyway. I wouldn't make a habit of that but it's a possibility. Third, and very important, what are your implied odds if you hit your hand. And when I say hit your hand I'm not talking about just top pair here. I will often just check-fold top pair against a few opponents with a hand like J9s. I'm looking to flop two pair, trips, pair and a draw, etc. The chance of that happening is about 20 to 1. So if you don't have at least 20 to 1 implied odds it's not worth playing in a multi-way pot.