Twenty minutes a season keeps windows working properly and catches small problems while they are still small.
Wash the glass and wipe down the frames with mild soap and water. Vacuum the tracks and clear the small weep holes at the bottom of the exterior sill so water can drain out instead of sitting in the track.
Check the screens for tears, and open and close every window in the house. Anything that binds or drags now will be worse in the cold. Look at exterior caulk on the sunny elevations, where it fails first.
Run your hand around the edge of each sash on a windy day and note any drafts. Inspect the weatherstripping for flattened or cracked sections. Lubricate locks, hinges and rollers with a dry lubricant, not an oil that collects grit.
Watch for condensation. A little on the inside glass on a very cold morning is normal. Persistent moisture, fog between panes, or water pooling on the sill is worth looking at properly. Keep locks engaged, since a locked sash seals tighter than an unlocked one.
Skip abrasive pads, razor blades on coated glass, and harsh solvents on vinyl or painted wood. They do damage that maintenance cannot undo.
Fogged glass, rot in the frame, water staining on the wall, or a sash that no longer closes square are past the point of upkeep. Those are worth having someone look at.
Call and we will come out, look at it, and tell you if it needs replacing.
No forms, no waiting on email.