Pretty much every job I’ve ever had has been “Here’s our infinite wish list of stuff we’d like. Do as much as you can.” Thus my work is never “done”. I just end my day when I feel I have met my professional responsibilities and my employers accept they are getting their money’s worth. (Obviously occasional deadline rushes excepted.)
It works nicely when the contract with myself is “they get all the hours in an eight hour workday”. It doesn’t work so well when I’m working from home and not quite disciplined enough to lock myself away for the requisite hours. So then I end up having “how much of the last hour should I really count” discussions in my head.
I structure my life so that I need as little willpower as possible to get productively through the day. No snacks at home, no distractions at work, etc. The plague is messing with that :-(.