How long have you been playing? I have logged less than 20K hands online over the course of a YEAR because most of my play is in B&Ms. I don't know exactly how many hands I've played at every given limit and I really don't care, I've been examining my play continually the entire time.
By the time I'd been playing for five months or so, I kind of got to the point where I can "feel" if I'm beating a game or not. The first time I took a shot at 30/3 SNGs, I cashed in the first four or five in a row but realized it was dumb luck (as I was making some big mistakes/getting in situations where I wasn't sure what to do) and dropped back down/went back to focusing on limit for awhile. This month I took a shot at 50/5's, dropped what I admit is a little more money than I was completely comfortable losing in the beginning but was able to say things like, "Well, you pushed all-in into a player you had read as weak-tight who suddenly lost his mind and made a call that was -EV according to ICM even if I was pushing any two cards." Even if you could argue that it was my read that was incorrect, it's through analysis like this that I feel I can tell the difference between bad luck and inadequate play at the new limit for the most part, and I'm willing to drop down
either way if the losses get too heavy.
I don't think it's necessary to say "You need n number of hands to move up," as long as you can objectively examine your game
at all times and move down if you think you're faltering. If you don't have that kind of self-awareness that's different, but even in that case there's no "magic number" involved, and I'd still say the answer is "If you feel like moving up and you're bankrolled for it, go ahead and take a small shot regardless of hands played and see how you feel about it, and move down if you have an early losing streak." There's nothing wrong with trying to move up, giving up, then trying again a couple months later until you get the hang of it. Or if you multitable you could use the 1xtable at new limit, several tables at old limit so you can try it without hurting yourself too bad (because your wins at your safe limit subsidize your losses at the new limit).
EDIT: All my talk of self-evaluation made me think of
this post, as the questions I ask myself before a move-up are similar to the questions I ask whether I should stay in a game; although "What should I do? I'm not sure." moments do count toward whether I think I'm ready for that limit yet or not.