Basically, my rule is at least 60 buy-ins for tournaments. For example, if you have a bankroll of $100, then entering tournaments with $5 buy-in is not so good, but entering the ones with $1 is good. If you start to increase your bankroll to a level where entering more expensive tournaments may be possible, then you can start playing such tournaments a little earlier. Maybe just to get a feeling about them. This bankroll management rule is meant to be bent (but not broken). Once you get your bankroll to about 150 buy-ins, you can take a step up the ladder more permanently.