What should I check each year to keep attic and wall insulation performing?

Insulation is easy to forget once the drywall is finished, but its performance can change through moisture, pests, compression, settling, or failed air sealing. I’m looking for a practical maintenance routine rather than another pre-drywall inspection checklist.

For accessible attic areas, I’d expect periodic checks for thin or uneven coverage, displaced blown cellulose or fiberglass, compressed batts around stored items, damp spots, staining, musty odors, and evidence of rodents or insects. Roof leaks, bathroom exhaust problems, and blocked soffit ventilation seem especially important because insulation can remain wet or contaminated after the original cause is no longer obvious. In a crawlspace, I’d also check whether insulation has sagged, become wet, or been damaged by plumbing work.

Exterior-wall problems are harder to see. Uneven room temperatures, recurring cold or warm strips along walls, drafts at outlets or trim, peeling paint, odors, and a gradual rise in heating or cooling use could point to insulation gaps, air leakage, or moisture rather than an HVAC issue. An infrared scan can be useful under suitable temperature conditions, but I’m wary of treating a single scan as proof of a defect.

My tentative schedule would be a visual attic and crawlspace inspection twice a year, plus checks after roof leaks, plumbing leaks, pest activity, or major remodeling. I’d compare energy use and comfort over time, while accounting for weather and thermostat settings.

Which symptoms would justify an energy audit first, and which would call for opening a wall or bringing in an insulation or building-envelope professional? Also, are there maintenance concerns that differ substantially between blown cellulose, fiberglass batts, rigid foam, and spray foam once they’re concealed?