of hitting a set on the flop are 7.5:1. You can't afford to set-mine every hand at an aggressive table, at least not from early position. Also, at a full ring table, your 222 may be dominated by 777 or 888
or any other set on the flop, turn or river. If I'm pretty sure that I'm going to get raised pre-flop by reasonable players (i.e., not maniacs) and I'm in early position I will usually fold. If I'm in late position and the hand is unopened or maybe just one limper I will raise because I am planning on taking down the hand post without making the set. If I do make the set, then that is simply an unexpected bonus.