Ok, so one circumstance is when there is a "legal requirement to purge all files". That's certainly not "always" and not always as hard: one of my jobs was at an open source company, and there are plenty of those to go around these days; as a consultant, you may start with some base work to build off of that you keep the rights to as well...

This also assumes you never-ever used a personal device to access any of them either (they might be in caches or Trash/Recycle Bin) — and I agree that to satisfy such a legal requirement, you probably don't want to be using a personal device to access them at all.

Keeping things separate has some upsides, but also some downsides (multiple devices to lug around) — depending on their situation, everybody should choose their own compromise (granted, some engagement contracts will make that choice for you).

I've personally come to be very happy with hardware isolation as a method of mental compartmentalization.

E.g. choice of computer dictates choice of activity, I won't accidentally work on something when I'm not supposed to.

I've had paid-for open source gigs, and I have a bunch of open source work spread out on a bunch of machines.

Downsides are:

  - The bag gets heavy when I have multiple events for separate customers/events on the same day
  - For stuff that is shared between computers (e.g. open source projects), I can forget to git push

Fortunately, the most locked off machines never need for other computers to connect to them.

And yes, this came as a customer requirement, but I've decided to grow with the choice.

I don't trust process isolation on a single computer very much.