This is a discussion on Is 5NL beaten? within the online poker forums, in the Cash Games section; I beated 2 NL - 10bb/100 in 100k hands.
Now I play 5NL - 14bb/100 in 10k hands
When I should consider 5 NL beated?
Since you already spend so much time at 2NL, I dont see any problem in moving on to 10NL right away. Unless you withdrew your winnings, your bankroll is more than enough, and you can always move back to 5NL again, if you want to. The difference in play style between 5NL and 10NL is not nearly as big as between 2NL and 5NL. I would then probably play another 100k hands at 10NL before trying 25NL. Best of luck.
I think it's very personal and depends on what is comfortable for you. I tend to play much more relaxed when I have more money behind, I mean bank roll wise. You can also try higher limits and you things don't work out you can take a step back at lower limit.
I agree with what a few other people have said above me, if you're beating a level that low by a considerable margin I think it's fine to move up fairly aggressively so long as you're comfortable doing so financially.
The low stakes you pay a lot of rake and you don't play very good opponents, Ideally you want to move up to a level that challenges you so you can build you skill set as the most money is made at the highest levels you are going to end up playing profitably so getting to the skill level to play those games as fast as you can (While being comfortable with playing those stakes financially) is the way you are going to get the highest financial gain from the game