We have about 40. The oldest is around 17 years old. Our newest server is 9 years old. Our average server age is probably around 13 years old.

The most common failure that completely takes them out of commission is a popped capacitor on the motherboard. Never had it happen before the 10 year mark.

Never had memory failure. Have had disk failures, but those are easy to replace. Had one power supply failure, but it was a faulty batch and happened within 2 years of the server's life.