http://www.jeffbridges.com/widelux.html

Banding is something you want to ask about before you buy. I too was very lucky when I got my F7 (through APUG, actually - one of many great experiences here!).

I just exercised my lens regularly, I used the camera enough that it got enough exercise but simply moving it with your finger and letting it go back is enough. The info on Jeff Bridges' site is very good.