I work I Ag retail (agronomic services, chemical sales) and while we have an IT department, a decade ago I’d occasionally act as “local” tech support and double a coworker’s RAM when their combination of browser/office/database front ends stopped gracefully fitting in 4GB (and later 8GB). I would also migrate them from HDD’s to SSD’s, and set them up with backups.

But even I haven’t done that in several years now, once IT moved to providing 16GB memory and SSD’s as a baseline, there’s really nothing left in a box to upgrade. I’m quite happy enough to not have to care.

Something as simple as adding a stick of RAM might be worthwhile, but some upgrades will take more money in salary (you and the person whose computer you're working on) than the upgrade is actually worth. This is especially true if you replace several components one at a time in a what would otherwise be a single replace cycle.

This is especially true if the business is writing down the replaced hardware as depreciated capital, compared to say simply adding a stick of RAM.

Agreed, the only time I did upgrades on boxes is swapping out spinning disks for SSD, that saved me a whole upgrade cycle it was such an improvement.

They are often leased and have to be returned in the same condition at the end of the term.

I've generally been given additional decent-performance storage every year or two when working in video games, fairly reliably the case since 2000, seemingly regardless of company size. Somehow each new project would always require yet more working space (again), and projects would often overlap to some extent.

Aside from that, almost always a new PC - almost! When times haven't been so good, I've had spot upgrades.

All of the above is just a question of running the numbers and minimising for cost, I'm sure.