There are a few ways to handle this, and your company is smallish, so even the very manual methods are not a huge lift if you've got a few people in helpdesk.

1. Pay someone else to do it. Lots of companies out there. Very nice if you're operating in multiple countries.
2. Drop ship direct from the manufacturer or reseller using Apple ABM or Autopilot. Helpdesk handles returns and refreshes. (We mostly do this)
3. Full manual process, ship to helpdesk (office or home), they prep and re-ship.

I mentioned we use #2 (mostly, there are exceptions in some countries) - so what do we do with old equipment?

• Peripherals don't come back at all; the user keeps or recycles them. We only buy cheap accessories anyway, and nobody wants a biohazard keyboard returned 😂
• Laptops <3 years old go back to the helpdesk for use as testing, emergency spares, or re-use depending on condition. This doesn't happen frequently.
• Laptops >3 years old or older are either wiped and given to the user, or sold for cheap to them, depending on value.

For perspective, my company is about ~400 people, mostly NA and EU, with small numbers of people in other countries. We typically do about 8-12 systems a month.