I would think the typical HPE customer (e.g. us) buys servers and uses them for between 3-5 years, before buying new servers. The old (out of warranty) servers might be discarded, or might be reused as test hardware.
Non tech Fortune 500 IT shops regularly see their refresh budget cut in favor of new projects. Seeing some amount of 5,7,10+ year old hardware still in service isn't unusual.
