Huh, I always take it off when I shower or wash more than a couple dishes. I actually don't think I've been swimming or hand-washed my car since I started wearing it, but I'd probably take it off then too. If my hands are soaking wet, it can work its way off.
No idea why you'd take it off for any of the others. Maybe certain kinds of hand tools? Simple bands are usually fine even in professional kitchens. I'll admit I got a little worried when I got an induction stove, but my ring has yet to burn me while cooking.
Who takes off a ring to carry groceries or vacuum?



Agreed, but I don't really think of any power tool when I think of "hand tools". That's like hammers and screwdrivers and wrenches and stuff.
Drills, dremels, anything with a motor is a "power tool" to me. I take my ring off whenever I work with a power tool it could possibly get caught on.