I grew my relaxed hair (first relaxed Oct '09) out to about collar bone length and then in June or July of 2010 I chopped a bunch of it off in an angled bob, and had only a little bit still relaxed on the very front edges. I could have kept growing because I did just what you're doing now and my relaxed hair was so healthy the stylists I went to for trims were surprised because I had barely any split ends. But, I decided I wanted to jump on the curly hair band wagon again so I chopped most of it off. I've had my fun with short hair, now I've decided to grow it out again even though it's natural, so again I'm doing a lot of what you're doing just to keep it healthy.
I know there are some ladies on Long Hair Community forums that have grown theirs out MUCH longer than that when they've transitioned. The general consensus seems to be that it's worth the patience and work involved :-).
Wurly, fine, thin, moderately to heavily porous. Mod CG.