No-limit is a game of maximizing value. The name of the game is getting your opponents to put in money with inferior hands. You do not want to get into situations where you are making such big bets that you are getting weaker to fold and only stronger to continue on. The best way to do this is usually by playing your hands straight forward especially preflop.
One of the easiest ways to spot a weak player is to notice if he habitually limp reraises. Normally you lose more value than you gain. Although this technique can be useful while playing the short stack it is usually not implemented in the right way.
Let’s say that we are under the gun with AA and have a $1,200 stack in a $5-$10 game. The table is loose and raises routinely get three or four callers. We limp, a few others limp and the button raises to $65. It gets back to us and we make it $300. Everyone folds and we take down the pot. To some, this may seem like a victory. But what if we had just played our hand straight forward and opened to a normal size raise preflop? We then encourage the dominated holdings like KJ and QT to come in; hands that we can extract multiple streets of future value from. Players simply have trouble folding top pair especially at the lower levels.
The reason why weak players limp reraise so much is because they are scared to play post-flop. They’ve taken some bad beats with AA and KK and don’t know how to release when they are behind. They attempt to “protect their hand” with large bets not realizing that they are losing an incredible amount of value from weaker holdings.