I dunno if this will clarify or muddy...
But here are sixty or so opinions...
http://www.google.com/url?q=http://a...8ANbgOc3nCE8gg
I dunno, I did mine at 90k or so and the belt looked fine. I know, I know, you can't really tell from looking at it.
Bottom line is, it can't hurt, it's not too difficult to do yourself, so if you got the cash and the time, do it for peace of mind.
Bart