1. Granules in your gutters
Asphalt shingles are coated with mineral granules that protect the asphalt from UV. As the roof ages, granules wash off into your gutters with every rain. A few granules are normal at any age. A handful per downspout per storm means you're in the last 3-5 years. A cup or more means replacement is overdue. Check the bottom of every downspout after the next rain.
2. Curling, cupping, or clawing edges
When asphalt shingles dry out from UV exposure, the edges curl up like potato chips. Cupping is when the corners turn up; clawing is when the middle of the shingle bows up while edges stay flat. Both indicate the shingle has lost flexibility and is days to weeks from cracking in the next wind event.
3. Missing shingles
Wind events progressively strip shingles off an aging roof. One missing shingle is a repair. A dozen missing across multiple slopes is a replacement, because the remaining shingles have all lost their bond and will follow within 1-2 storm seasons.
4. Sagging or wavy roof line — STOP, this is structural
If your roof line dips, sags, or looks wavy from the curb, you have water damage to the deck or rafters underneath. This is no longer a roofing problem — it's a structural problem. Stop reading articles, get a structural engineer or experienced roofer to inspect immediately. Sagging decks can collapse under snow load or during a normal walk-on inspection.
5. Daylight in the attic
Go into your attic on a sunny day with the lights off. Look up. If you see daylight anywhere besides the vents, you have a hole. Sometimes a small repair fixes it. If you see daylight in multiple spots, the deck is failing and a replacement is needed.
6. Stains on interior ceilings
Brown rings or yellowish stains on ceilings or upper-floor walls mean water has been getting in for some time. The stain you can see is downstream of a much larger wet area in the insulation above. Get a roof inspection within 30 days, ideally on the next dry day.
7. Moss or algae across whole slopes
Spotty algae streaks are cosmetic. A full carpet of moss across the north-facing slope is a problem — moss holds moisture against the roof deck and rots both shingles and underlying wood. Once it's covering more than ~30% of a slope, you're looking at significant deck damage.
8. Flashing failures
Flashing is the metal trim around chimneys, skylights, and vent pipes. It almost always fails before the surrounding shingles do. Rusted, lifted, or missing flashing is the #1 source of leaks on otherwise-OK roofs. If your flashing is shot but the shingles are sound, that's a flashing repair, not a replacement.
9. Roof age over 80% of expected lifespan
This is the math approach. If your asphalt shingle roof is over 20 years old, you're at end-of-life regardless of how it looks. Insurance carriers will start denying claims as 'wear and tear,' depreciation on any settlement will be steep, and a single major storm will turn into a full replacement anyway. Replacing proactively before storm damage gives you choice; replacing reactively after damage means you're at the mercy of an insurance scope.
10. Energy bills creeping up
An aging roof loses thermal performance — the deck warps, ventilation channels get blocked by debris, and the attic insulation gets soaked from minor leaks you can't see. If your summer cooling bills are climbing year-over-year despite no other changes, the roof might be the culprit. This is the most under-recognized sign because most homeowners blame the AC.