Most roof problems give early signals. Catching them early usually means a smaller repair.
1. Stains on ceilings or walls
Brown or yellow rings often mean water is getting in somewhere above.
2. Granules in the gutters
Shingles shed granules as they age. Heavy amounts can mean they're wearing out.
3. Missing or lifted shingles
Look from the yard with binoculars after windy weather.
4. Daylight in the attic
If you see light through the roof boards, water can get in too.
5. Age
If your roof is 15 or more years old, a check-up is a good idea even without symptoms.