The clearest signal is repeat repairs: **if you’ve patched the same roof three times in two years, you’re funding a replacement one leak at a time.**
Signs that point to replacement:
– **Age past 18 years on architectural shingles.** Repairs near end of life rarely hold, because the surrounding shingles are equally brittle.
– **Curling, cupping, or clawing edges.** Shingles lifting at the corners have lost flexibility — that’s material failure across the whole roof.
– **Bald patches and heavy granule loss.** Granules are the UV shield, and there’s no way to put them back.
– **A sagging or spongy deck.** Visible dips mean water already reached the plywood. This is structural and worsens on its own.
– **Daylight visible through the attic boards.** If light gets in, so does water.
– **Multiple leaks in different areas.** One leak is a flashing problem. Three in three locations is a finished system.
**Repair is still right** when the roof is under about twelve years old, the damage is confined to one area, and the cause is identifiable — a failed pipe boot, storm-lifted ridge cap, damaged chimney flashing.
The arithmetic that settles it: divide repair cost by the years it realistically buys. When that annual figure approaches replacement cost divided by 20 years, replacement is the better value.