This question is a black hole. I am not sure there is any correct answer, as you can always improve. That being said I believe when you can consistently beat a certain level (over a reasonable sample size) then it is time to move up. Maybe you are making $500 a week at 1/2 and you need this money to pay rent. Well shit stick with 1/2 and keep improving there, but in order to see better profits eventually you'll have to play at a higher level. I think a person could make a decent living multi tabling 2/4 actually. Some may disagree , but you could pull 50k a year on 2/4. So again what is your ultimate goal. personally I wouldn't be happy being a great player vs. decent players I would rather work at getting better and better against excellent players (10/20 +) 10/20 I would imagine is %50 professional players.