One of the reasons you shouldn't jump into a $5/10 game after winning a huge bunch of money at $2/4 is because as the stakes rise, so does the average skill level of the players sitting there. You want to be one of the best at the table, not the fish who sits down with sharks. If you're making stacks of money at a lower level game, why move? You're winning stacks of money. The swings up & down at higher limits are much bigger, and one big night's win won't last long at a high-stakes game.