Airbnb cost seg, answered plainly.

There are seven tests. For most self‑managing STR owners, the winning one is: 100+ hours AND more than anyone else touching the property. That means you have to out‑hour your cleaner, your handyman, your co‑host — combined individually, not combined total.

What counts: guest communication, listing maintenance, pricing, turnover coordination, restocking trips, repairs you do yourself, bookkeeping, travel to the property. What doesn't: time spent as an investor (reading about real estate, attending seminars) or time your spouse spends if filing separately.

Keep a contemporaneous log. "I was involved" is not a defense in audit.

Probably not for that year — the PM usually spent more hours than you, which breaks the "more than anyone else" test. The depreciation loss becomes passive and suspends forward.

Two paths forward: (1) transition to self‑management this year and do the study for the current tax year, or (2) keep the suspended passive loss on file — it releases whenever you sell the property or generate enough passive income.

You can do it any year you own the property. The IRS allows a "catch‑up" adjustment (Form 3115) that lets you claim all the depreciation you should have taken in prior years — in a single current‑year deduction. No amended returns required.

This is often the biggest single benefit for existing hosts: a property you've held for 3–5 years can generate a larger year‑one deduction than one you just bought, because you're catching up multiple years at once.

Depreciation recapture is real. When you sell, the IRS taxes recaptured depreciation at up to 25% (Section 1250) for the building portion, and at ordinary rates for the 5/7‑year components.

But — and this is the important part — you've had the use of those dollars for years, tax‑free, at the cost of paying them back later at a capped rate. If you 1031 exchange into a like‑kind replacement property, you can defer recapture entirely. Most investors model this as "defer, defer, step up at death" with their CPA.

Average. Total rented days divided by total guest stays. A one‑off 14‑day booking doesn't disqualify you if your year average is still 7 days or less.

Grab your Airbnb earnings summary and count nights per reservation. Most vacation‑market STRs come in at 3–5 nights; urban weekend rentals often 2–3. If you're running a "corporate housing" model with 30+ day stays, you're probably not clearing the rule and should talk to your CPA about a different strategy.

A bound PDF deliverable, typically 30–80 pages. It includes: a description of the engineering methodology, photographs of the property (often from your own phone), a full itemized component list with cost estimates per class life, a depreciation schedule showing year‑by‑year deductions, and a summary your CPA attaches to your return as support.

Turnaround is usually 3–4 weeks from intake. You do not need an on‑site visit for most residential STRs — detailed photos, the appraisal, and closing documents are enough.

Marginally, and not in the way people imagine. Cost seg itself is a well‑established IRS‑sanctioned methodology (see the IRS Cost Segregation Audit Techniques Guide). An engineered study from a credentialed provider is strong audit documentation, not a red flag.

What does draw scrutiny: claiming an STR loss against W‑2 income without a material participation log, claiming reclassification percentages inconsistent with the property type, or using a low‑cost "software‑only" study without engineering support. If you're audited, your study is your defense — make sure it's a good one.