If you ever stop learning in poker, your never going to achieve your potential. You need to constantly work on improving your game. Whether it be adjusting to regs, improoving your ITM play, upping the volume played, upping the amount of time spent reviewing. There's always something you can be improoving on, Hell, i've been playing SNG for years, and today im making a radical change to the way i view the game. I think some players tend to play well for a period of time, then their play becomes stagnant. They continue to make the same plays, they don't bother to review as much. THey get lazy. They might open their range up from 14% to 16%. They might start making moderately bad shoves/calls of shoves etc.
Point is this. Keep learning and improving, i guarantee the best players in the world still learn new things day to day, and constantly work hard at their game.
...but bad habits come back! 
