A CPA's quick reference: when residential cost segregation is worth recommending.

If you prepare returns for residential real estate investors, you already field the cost segregation question — usually after a client watches a video and shows up convinced it's free money. The honest answer is that residential cost segregation is worth recommending more often than most CPAs reach for it, and worth skipping more often than most cost-seg salespeople admit. The trick is knowing which side of that line a given client is on without running a full analysis for every rental on the books. This is the quick reference I'd want on the desk.

Four variables decide it.

Almost every residential case comes down to four inputs: the depreciable basis of the property, the client's marginal tax rate, how long they intend to hold, and whether they can actually use the deduction this year. Get those four and you can call the outcome in about ninety seconds. Everything else — property type, location, the specific mix of short-life assets — affects the size of the number, not the direction of the decision.

Basis sets the ceiling. Marginal rate sets the value of the deduction. Holding period determines whether recapture eventually claws part of it back. And usability — passive versus active, whether there's passive income or other offsets — decides whether the deduction does anything for them in the year they want it.

A rule of thumb on property value.

For a straightforward long-term residential rental, the study tends to pencil once depreciable basis clears roughly $300K–$350K and the client is in a 32% bracket or higher. Below that, the year-one benefit can still beat the fixed-fee cost of the study, but the margin gets thin enough that it's worth a closer look rather than a reflexive yes.

Here's the worked example I use. A $525K single-family rental, placed in service in 2026, with 80% of the price treated as depreciable basis after carving out land — that's $420K of basis. A reasonable residential study reclassifies around 22% of that into 5-, 7-, and 15-year property, so roughly $92K moves out of the 27.5-year schedule. With 100% bonus depreciation back in effect for property placed in service after January 19, 2025, that full $92K is deductible in year one. At a 35% marginal federal rate, that's about $32,000 of year-one tax savings against a $1,750 study fee. The direction of that decision isn't close.

When it clearly pencils.

Recommend it without much hesitation when the client has meaningful basis, a high marginal rate, a multi-year hold horizon, and a way to use the loss — either passive income from other properties, real estate professional status, or the short-term rental treatment below. New acquisitions are the cleanest case, but a look-back study on property placed in service in prior years is often more compelling, because a §481(a) adjustment lets the client catch the cumulative missed depreciation in the current year without amending a single return.

When to skip it, or at least slow down.

Be candid with clients in these situations: basis is low and the bracket is modest, so the absolute dollars are small; the client plans to sell within a year or two, where depreciation recapture erodes much of the benefit; or the client has no passive income and no path to using the loss, leaving it suspended under the passive activity rules until a future disposition. A suspended loss isn't worthless — it releases on sale — but if the pitch was "deduct it this year," that pitch doesn't hold. Property held in a dealer capacity, or properties about to be 1031'd into something else, also deserve a second look before you recommend a study.

The short-term rental exception worth flagging.

The biggest swing factor for high-income clients is the short-term rental treatment. A materially participating STR owner can take cost-seg losses against W-2 and other active income, not just passive real estate income — which changes the answer for a high earner who'd otherwise have a suspended loss. It comes with real documentation requirements, and it's worth understanding before you recommend it; I walk through the mechanics in the short-term rental loophole, explained without the YouTube fluff.

How to refer without losing the relationship.

When a study makes sense, you don't have to run it yourself. We work alongside the CPA and never poach the relationship — the deliverable is built so you can implement the numbers without translating anything, and it's audit-ready, with the methodology and asset detail a reviewer would expect to see. If you'd rather just get a candid read on a specific property before deciding, a short feasibility call gets you a yes or no and a fixed-fee quote if it's worth doing.