The instinct with a dragging door is to remove material. That is usually the wrong first move, and it is irreversible.
Step one: find where it rubs
Close the door slowly and watch. Slide a piece of paper around the perimeter to find where the gap closes up. Note whether the contact is at the top of the latch side, the bottom of the latch side, along the top edge, or at the threshold. That location tells you the cause.
The most common cause: loose hinge screws
If the door rubs at the top of the latch side or the upper corner, the door is sagging – the top hinge is pulling away from the jamb.
Open the door, take the weight off it, and try tightening the top hinge screws. If a screw spins without biting, the hole is stripped. The proper fix takes ten minutes: remove the screw, fill the hole with a wooden dowel or glued wood splinters, let it set, and drive a new screw into fresh wood.
Better still, replace one screw in the top hinge with a screw long enough to pass through the jamb and reach the framing behind it. That single change fixes an enormous proportion of sagging doors permanently.
Second cause: seasonal swelling
If the door only sticks in humid months and closes fine the rest of the year, the wood is swelling. Removing material solves it today and leaves you with a gappy door in the dry season. Live with it, or address the humidity.
Third cause: the frame has moved
Houses settle. If the gap around the door is visibly wider at one corner than the diagonal opposite, the opening is out of square. Adjusting hinge positions with shims behind one leaf can often recover enough clearance.
Last resort: remove material
Only after ruling out the above. Mark exactly where it binds, take the door down, and remove a little at a time from the hinge side where possible – the latch side edge is more visible and harder to make look right. Refinish any wood you expose, especially on the top and bottom edges, or the bare wood will absorb moisture and swell.
Do not skip this
Whatever you do, finish the cut edges. Unfinished edges are how a fixed door becomes a sticking door again next summer.
