Stiff locks and sticking doors: easy wins first

First, find out which part is fighting you

Open the door and try everything with it standing open. Turn the key, lift the handle, throw the bolt. If the lock is stiff even with the door open, the problem lives in the lock or cylinder. If everything moves sweetly until the door is closed, the door and frame are out of line and the lock is innocent.

That one test decides your afternoon: lock care in the first case, hinges and strike plates in the second.

The oil myth

Oil and multi-purpose maintenance sprays feel like the obvious answer, and in a cylinder they are the classic mistake: the film attracts dust and fluff, and the mixture packs the pins with grime until the lock is worse than before. Graphite for cylinders; PTFE or silicone for latches, bolts and hinges. That one rule prevents most repeat performances, and it applies equally to a garage door that grinds and sticks.

Timber doors also breathe with the weather. A door that sticks every autumn and frees itself in spring is swelling, not failing, so resist planing it at the damp peak of winter or you will pay for it with a draught in July. Wait for a dry week, remove the minimum, and paint or seal the bare edge so it stops drinking moisture. If the door is uPVC rather than timber, sticking is usually an alignment problem in the multipoint lock, which has its own fix.

Replace the lock before it locks you out

Locks rarely die without warning; they get harder to turn for weeks first. A cylinder replaced on your schedule is a small planned job, and on many doors a competent DIYer can do it: one retaining screw in the door edge, key turned slightly to free the cam, old cylinder out, measured, matched and swapped. The same failure at 11pm becomes an emergency call-out, possibly a drilled lock, and a colder doorstep than anyone deserves.

If you are replacing anyway, upgrade: a TS007 three-star anti-snap cylinder costs little more than a basic one, and the security walk-round guide explains the standards insurers look for. Just moved in? Fresh cylinders belong on the first-week list, because you never know how many keys are still out there.