If you had two springs with the same seat & same open pressures, and same installed heights,

but one spring is 1.625 diameter and one is 1.375 diameter, which one will last longer under the same operating conditions ?

I think the bigger spring probably would have a smaller wire diameter (not sure on that).

I think spring rating would come into play as well, but definately think the larger dia spring would hold its value longer.

Maybe a different way of looking at it but I'll take the smaller spring. I like PSI and feel like you can use a spring with less pressure if you're significantly reducing weight