We always use the best. These small but critical parts of a vehicle do so much but get little respect.
Most car manufactures have a recommended replacement schedule that can be subjective. Surprisingly some have NONE! It is best to adhere to a schedule unless there is a good reason not to. If a progressive corrosion has set in the hoses then best to replace sooner than scheduled. The CAUSE of the corrosion should also be addressed at that time to prevent further premature age and break down.
The belts may also fail prematurely if the vehicle sits for extended periods of time in an extreme atmosphere such as a high heat as in the desert, or near salt air such as here in Huntington Beach or surrounding areas.
In fairness to todays vehicles, many belts and hoses go over 100,000 miles. However it may have been in a short period of time so AGE is not so much a factor as USE. Because we've seen more than most, it has been our policy to consider age or use to determine replacement or preventative maintenance.
It amuses us that many of the latter model vehicles have only one belt and as many as 27 hoses!