I bounce back in forth btw EXP and Plat. I find that if I book early (I'm booking now for Nov), I usually get upgraded. I like that if I commit at that level, I don't get shoved aside by a last minute buyer. Commitment counts for a lot and if I want to make sure, as in the overnight LAX-JFK, I dump some miles. It is a benefit, not an expectation and I really try to treat it as such. Makes life and flying much easier.