Be aware that garage doors are heavy, springs are powerful and potentially dangerous

All safety rules must be followed

If you have no particular diy skills or knowledge:

Keep everything clean. Regularly wash the door. Use warm soapy water. Do this frequently if you live within three miles of the sea

Manufacturers typically will not honour a warranty claim for corrosion within three miles of the sea.

Occasionally (say once per year):

Clean the tracks where the wheels or rollers travel. They should be dry and clean.

For manual doors check that the door opens and closes easily. The door should lift by itself and be very easily pushed to fully open (just one finger).

Check that the locks work. Lock the door and push or rattle it to make sure it is firmly locked.

For motorised doors check all handsets work. The 'spare' one might be needed one day, no use if its battery is flat. Check and listen for any unusual noises.

If you have good diy skills:

Add to the above a visual check of all parts. Check nothing is loose or broken.

Check the manufacturers advice on maintenance where available.

In general lubricate all hinges, pivots and roller bearings (not tracks or rollers themselves)

Test the safety system on electric doors. Don't put anything solid in the way of the door - although it should of course stop, if it did not then it potentially could break. Stand safely clear of the door and stop it with your hand. It should stop without excessive down force, and should then open a little way and stop.

If the door has an external release lock, use it to make sure it works.