I think I played for two or three years before I canceled the first time. I've probably canceled three times since then, usually for a few months when I realize that I haven't logged in for a few weeks. In that time I play other games and do other stuff, then wind up resubscribing. Games like this draw you in and you wind up playing on a regular schedule (even as a casual player), and that is bound to lead to burnout.

There are so many games out there that it would be crazy to force yourself to play WOW if it's not fun. I have a backlog of console games that I'll get to at some point, when WOW becomes boring again.