Visible roof warnings
Widespread curling, cracking, missing material, exposed reinforcement, corrosion, open seams, failed flashings, and repeated patches deserve professional evaluation.
Interior and attic clues
Recurring stains, damp insulation, mold-like growth, daylight through the deck, rusted fasteners, and persistent condensation can indicate water entry or ventilation problems.
Repair or replace
Localized damage on a serviceable roof may justify repair. Multiple leak zones, brittle material, widespread deck damage, incompatible prior work, or an assembly near the end of its useful life can make replacement more predictable.