Wood absorbs moisture from humid air and swells across its width, so the door grows a millimetre or two in summer and shrinks back when the air dries. Plane it in August and you will have a draughty gap by January — adjust the hinges or the strike plate instead.
Find out where it is actually binding
Close the door slowly and watch the gap all the way round, or slide a sheet of paper down the edge until it jams. That tells you the exact point of contact, which is usually one of three places: the top corner on the latch side, the whole latch edge, or the bottom against the threshold.
Do this in the season it is sticking. A door that binds in September tells you nothing useful in February.
The order to try things
1. Tighten the hinge screws
Free, takes two minutes, and fixes this more often than anything else. Hinge screws work loose, the door drops on its hinges, and the top latch-side corner starts catching the frame. If a screw spins without biting, the hole is stripped — glue a couple of matchsticks or a golf tee into it, let it set, and drive the screw again. If you can reach it, one long screw through the top hinge into the framing behind the jamb pulls a dropped door back square.
2. Move the strike plate
If the latch is catching on the plate rather than the door rubbing on the frame, unscrew the strike plate, move it a couple of millimetres, and re-drill. A small file on the strike opening is often enough and is completely reversible.
3. Only then, remove material
And if you must, take it off the hinge side by deepening the mortises slightly, not the latch side. Planing the latch edge in peak humidity is the classic mistake — you are trimming the door to its largest size of the year, and every dry month afterwards you live with a visible gap and a latch that barely catches.
Seal the edges while it is off
Most interior doors are only finished on the two faces. The top and bottom edges are usually raw timber, which is exactly where the humidity gets in. If you have the door off for any reason, put a coat of paint or sealer on all four edges. It genuinely slows the seasonal swing.
When it is not the door
A door that has started binding and never unbinds — especially with a new crack in the drywall at the top corner of the frame, or a floor that feels uneven near the doorway — is a movement problem in the structure rather than a moisture problem in the timber. On a slab in this area that is worth someone looking at properly rather than shaving the door until it closes.