Belt changes: miles, years or appearance?

[Donald]

I carry a spare drive belt (and exhaust gas temp sensor) in a giant Ziploc bag.

 

[BrendanC]

every 50k with gates green HD belts. breaking a belt is not something i take lightly.

 

[JHZR2]

I’ve typically done it if I start to see cranking, hear noise, etc.

I just did the serpentine and timing belt on our Odyssey. They were practically like new at 100k.

That serpentine belt was perfect. I replaced it anyway.