The door for our half-bathroom was sticking. I investigated, and determined that the issue was that the hinges were bent; here’s an old hinge after being removed:

So I removed the door to replace the hinges:

The old hinges were non-mortise, i.e. designed for surface mounting. But I determined that there was enough room for regular hinges, so bought some of a similar size (with a removable pin, for safety):

An installed hinge:

The half bath door works much better now: