This is the range of homes I see catch buyers and sellers off guard the most, because these houses don't look old. They usually have decent bones, updated-looking finishes, and no obvious red flags on a drive-by. But four big-ticket items are quietly running out of runway at the same time - and it's rarely on anyone's radar until an inspector flags it or something fails.

Standard asphalt composition shingles last roughly 20–25 years in our climate, less with budget-grade shingles or heavy moss growth from Pacific Northwest rain. A full replacement runs $15,000–$30,000 depending on size and material, and nationally recoups only about 60–68% of its cost at resale - that's a lower percentage than a lot of homeowners expect. But that ROI number is measuring the wrong thing: a roof isn't there to "add" value, it's there to keep itself off the inspection report. A home with a visibly worn or original-to-1998 roof gives buyers a straightforward, hard-to-negotiate-around repair credit request.

Furnaces typically last 15–20 years, and AC units or heat pumps closer to 12–15 years. A full system replacement runs $11,500–$14,000 on average today. Worth knowing if your system is aging: the HVAC industry has been transitioning refrigerants - R-410A systems are being phased out in favor of the newer R-454B standard, and recharge costs on older refrigerant have been climbing as supply tightens. A system that's still running but getting expensive to service is often a sign it's time to plan the replacement rather than keep patching it.

Standard tank water heaters last about 8–12 years, and full replacement runs $1,200–$4,500. That means a home built in this era isn't necessarily on its original unit - it may already be on its second or third - so the real question isn't "how old is the house," it's "how old is this specific water heater." Check the install date on the unit itself; don't assume.

This is the one I see skipped in almost every generic "home improvement" list, and it matters a lot for this era specifically. CPVC pipe has been standard for hot and cold water lines since the 1980s, and it becomes brittle after roughly 25–30 years - especially with chlorinated water or sun/UV exposure on exposed runs. A home built in the late 1990s or early 2000s is right in that window now. Polybutylene pipe ("poly-B"), common roughly from the late 1970s through the mid-1990s, is the more serious version of this problem: it deteriorates from chlorine in the water supply and tends to fail suddenly rather than gradually, and many insurance companies won't cover it at all or will cancel a policy outright once they know it's present.

A whole-home replumb isn't cheap, but it's a known, budgetable number - on a 2,000 sq ft two-story home, expect around $20,000 for a full repipe. That's a real cost to plan for, but it's a fixed, one-time number versus an unpredictable pipe failure and water damage claim. It's also exactly the kind of question I get from first-time buyers trying to read between the lines on an older listing - is that roof newer, or is it 25 years old?