How hard you drive a car has nothing to do with the timing belt. This is not a wear item (like brakes, tires, etc), it detroriates over time. Depending on environmental factors, it can last forever or break early. I always replace mine at 60k (I don't replace the water pump - don't believe in fixing stuff that ain't broke). I recommend replacing it early, only because, the timing belt is one of the few items that, when it goes, can take your whole engine with it. It's just not worth the risk IMHO.

I guess if the car is relatively new, with high mileage, I'd wait 'till 90K. But if it's got a few years on it - and the other belts are starting to look old, I'd probably change it. I realize that Honda recommends 90K, but my mother-in-law followed that advice with her Civic and wound up with a dead car. You gotta remember, when you're selling a car (as in new), marketing it as not having to make a major repair until later in the car's life, is a selling point. But once you've got the car, and you're past 50K (powertrain warranty), Honda could care less whether or not your timing belt snaps.