It is more about when you are ready (I.e. comfortably winning at 2NL) and have the right bankroll. So it will very much vary from person to person, but I wouldn't rush and think it is likely to take months rather than weeks.
In terms of bankroll requirements ideally you would want 40 buy ins at 5NL before moving up, I.e. $200, so it will take a while to get there. You could shot take sooner, e.g. at $100, 20 buy ins, but you must be prepared to move back down should it not go well and you lose say 4 or 5 buy ins.
Personally I moved up from 2NL to 5NL too soon and had to move back down.
I think
@Station_Master had put everything in a clear way, it all depends on many things. I just would like to add that you have to know your own game style applied to your bankroll management: if you are more tight it would be required less buy-ins.
And paraphrasing our dear mate, never be in a rush or in a hurry to climb stakes: look to the stakes as of semesters of a graduation/college course: in the first semester we must master the basics and the fundamentals of poker, and we are approved in these disciplines by beating NLHE 2.
The second semester we are going to get deeper into meta-thinking, value of position, etc
The comparison is just didactic to illustrate how complicated things can be under the terms of praxis and theory. (I’m not stating by any means that it should take 6 months for us to climb to one stake to another, or that the mentioned contents are going to be the same)
But I continue with this comparison, and when we get in the 5th semester (NLHE 25) we must have a very complete mindset, a profound experience and knowledge of balancing (GTO) and be very good in reading hands and opponents, just to begin with.
At least in
pokerstars, where at NLHE 10 we would already find very sophisticated and even hard average regulars: even the fishes are tough.
Most important than quantity is quality, so do not trouble yourself making plans for weeks or months to come, keep studying, participating here in the forum and let the chips fall as they may!