I work at an ewaste recycling company. Most of what we get is corporate IT department decommissions. It seems like most companies run things for about 5 to 10 years, as most desktops, laptops, and servers I've seen lately have 4th to 10th gen Intel CPUs, peaking around 8th gen. We occasionally get something with DDR5, but it's rare and often broken. If anything is sufficiently valuable, we try to resell it.[0]

[0] https://www.ebay.com/str/evolutionecycling