What mistakes do homeowners make about winter pests?

Both land at the top for the same reason: they're about denying entry, not reacting after the fact. Sealing quarter-inch gaps before the first hard frost stops rodents from getting in at all, which extension and federal exclusion guidance treat as the most effective, durable control available — more effective than anything applied afterward. Swapping plastic storage bins for metal or glass removes the second common failure point, because rodent incisors defeat plastic easily but cannot defeat metal or glass. Neither costs much money, and both are typically homeowner-doable in an afternoon.

Two items on this list aren't errors of omission so much as misunderstandings worth correcting. Not keeping a written service or inspection record is a real but secondary miss — useful for warranties and any insurance claim tied to a secondary loss, but it doesn't prevent anything by itself. Assuming homeowners insurance covers rodent damage is the costlier misunderstanding: standard policies generally treat this damage as preventable maintenance and exclude it, so the expectation itself needs resetting, not just the paperwork.

Peppermint oil and similar repellents are cheap, pleasant to use, and give a genuine sense of having done something today — which is exactly why they're popular, and it's worth naming that honestly rather than mocking it. But the evidence shows the effect fades quickly and doesn't hold up against an established population. Ultrasonic and electronic repellers rank lower still: the FTC's own enforcement history against manufacturers making unsupported efficacy claims is a strong, independent signal that these products don't do what they're marketed to do.