Roof replacement vs repair: when each makes sense
The 'repair vs replace' decision is the highest-stakes call a homeowner makes about their roof. Get it wrong on the cheap side and you pay twice. Get it wrong on the expensive side and you spent $15K when $1.5K would have done. Here's the framework.
Pure repair territory
Single missing/damaged shingle area (less than 50 sq ft). Flashing issue around a vent or skylight. Single leak with clear damage source. Roof under 10 years old with one isolated problem. Repair cost typically $300–$1,200; expect that to last as long as the rest of the roof.
Repair-or-partial-replacement zone (judgment call)
10–15 year old roof with 1–2 problem areas. Hail damage covered by insurance. Localized storm damage on one slope. This is where you get multiple quotes and may negotiate with insurance. A partial replacement (one slope) costs 30–50% of full replacement.
Replace from the start
Roof 18+ years old (asphalt). Multiple leaks across the roof. Granule loss visible in gutters. Daylight visible through deck. Curling, cupping, or balding shingles widespread. Decking damage. Multiple repair calls in 24 months. At this point, repair is throwing money at a roof that's at end of life.
Insurance-driven decisions
After a hail or wind event, get an inspection from BOTH a roofer and your insurance adjuster (separately, with photos). If insurance is paying, replacement often makes sense even if a repair would technically work — you're getting a 20-year asset for a deductible. If insurance denies and you'd be self-paying, the math is different.
Roofs over 18 years almost always replace. Roofs under 10 years almost always repair. The middle requires judgment, multiple quotes, and (post-storm) careful insurance navigation. Get three opinions before making a 5-figure decision.