How to tell a roof is past repairing

Granules in the gutter

The granules are the sunscreen. Losing them in volume means the asphalt beneath is being cooked directly, and from that point the roof ages in years rather than decades.

Shingles that curl, cup or go brittle

A roof near the end goes hard. Shingles that were pliable enough to seal down in the sun no longer bond, and the first serious wind takes them.

Repeated repairs in different places

One leak is an event. Three leaks in three different areas inside two years is a pattern, and the pattern means the covering has reached the end of its service life rather than suffered a specific failure.

Sagging along a line

A ridge or a plane that dips is a structural signal rather than a covering one. It usually means decking that has been wet long enough to lose strength, and occasionally framing. This is the one symptom that should not wait.

The age on the paperwork

Age alone is not a reason to replace. Age plus any one of the symptoms above usually is.

Daylight or damp in the attic

The attic tells the truth earlier than the ceiling does. Staining on the underside of the deck predates any stain you will see downstairs by a long way.

In short

None of these on their own settles it. Two together usually do. An inspection costs little and removes the guesswork entirely.