I disagree with the people who say that it's okay.
If you really want to play higher, deposit more money. If you can't, then you have to
grind it out.
First of all, if you do "move up" thinking that you'll move right
back down if "testing the waters" is unsuccessful and then you bust due to a
bad beat, was that really "testing the waters"? You're gonna be like, "dammit, I
busted out because of a
bad beat, which doesn't
tell me anything. I'll try another buyin and see how it goes." You could lose a significant portion of your
bankroll doing this, which is why you shouldn't do it. One of the functions of having a
bankroll and rules is to absorb busting due to bad beats and negative
variance.
Second of all, you are creating bad habits. When will it end? Right now you want to play out of your
bankroll because it's taking too long to move up to the next
level. It's
always going to be like that! You're always gonna have to
grind it out to try to increase your
roll enough to move up. For example, the proper
roll to play at NL25 is around $500. Say you have $150 right now and you're like, "Oh I'll just play it for a little while and see how I do", and then you luck out, win a few big pots, and actually get up to around the proper
roll to play at NL25. So you're all happy and now you can play NL25 legitimately, right? So you play NL25 for a while, lose a little, win a little, and finally get your
roll up to $650 after a while. But now the novelty is gone and it's going too slowly for you again. "Ah
well, I have 13 buyins for NL50 and it worked before ... let's just give it a try ..."
Start a bad habit and it'll probably stick with you for the rest of your poker "career" until you bust and realize you shouldn't have done it.
If you do not have the discipline to play at the lower levels and
grind it out following
bankroll rules/suggestions, then you do not have the discipline you need to be successful at poker. Discipline is required in every single aspect of this game, and
bankroll management is one of the biggest aspects of all. It's not even just the increased risk of busting your
roll, it's the fact that it shows you lack certain discipline needed to be a successful poker player, especially for poker players relatively new to the game.