The closet is this odd little half-height space which we had the contractor put in (because wasting potential storage under the stairs would be silly). It's accessible from either side of the stairs, so it needed two doors. But it wasn't in the original quote so they would have charged us to put doors on it (and it would have been a lot because they'd have to be custom).
So I said, 'leave it, I'll do it myself'. And I did! We had old hollow-core doors left over from the construction (the contractor put in new prehung doors instead of rehanging old ones). So I cut two of them down to 25 x 50 inches, cut and glued scrap lumber to fill in the edges, built doorframes, mortised the doors and frames, reinstalled the hinges, stained and polyurethaned the frames to match the existing woodwork and then installed the whole thing in the door opening, put on exterior trim and cut the baseboards to meet the new doorframe.
And the result- the door fits tightly with an even space all around, no gaps, no sticking, no squeaking. If you open it, it stays where you put it- not tending to swing open or shut (because it's plumb and level in all three axes). Any of these things would have annoyed me until the end of time. And because I used the old doors, they match everything else. I only had to buy a couple pieces of lumber for the frame and some strip pieces for the jamb- everything else I did with materials I already had. And it's *done*. In a project that seems like it will never end, that's big!