^^ Completely understand where you are coming from.
Obviously on a smaller scale, but at the shop I worked for years, we always assess the problems first, and then go from there. If it's something a few quick scans will fix up, we scan, run some maintenance stuff, and boom. Done.
But to properly assess the situation in the first place, we have to do some trial and error. For example, a problem we were having with a bunch of computers at one point was Malwarebytes refusing to install. You would actually have to change the name of the installer for it to work, and even then, you couldn't run it afterwards. It would just hang in the task manager and never pop up. Changing the .exe to run it didn't work either.
On machines like that, we decided to back up and reformat, because it was more trouble than it's worth. But Our first instinct isn't to format just because there's problems. Most customers would prefer it to not be formatted, even with the promise of backup, in my experience. So if there's a chance of cleaning it up, it's used as a last resort.