teaching has definitely helped me - a lot of the basics become instinctive after a while, but that doesn't mean that your implicit knowledge is not without flaws. teaching a beginner's class has forced me to re-analyze my basic techniques and has refreshed my knowledge and skill regarding solid, fundamental techniques that i tend to disfavor.
this is a pretty universal principle that isn't confined to bjj. i have a b.a. from an ivy league university, so i would like to think that my command of the english language is pretty solid, but sadly, it wasn't until i taught 2nd grade for a few years that i really solidified my knowledge of basic grammar and language principles.