I work in cost segregation, and there's one objection I hear from STR investors all the time: "Sure, year 1 is huge, but then the deductions dry up, and I'll pay it all back when I sell."

Here's why that thinking leaves money on the table. (This is an illustrative example, not a specific client. The numbers are rounded to keep the math simple.)

Meet "Dana." She's a W-2 earner in the 32% bracket who buys a $600K short-term rental. After land, her depreciable basis is $500K. Her average guest stay is under 7 days and she materially participates, so her rental losses can offset her W-2 income.

Without a study: about $18K of depreciation a year, spread over 27.5 years.

With a study: about $125K gets reclassified into 5-, 7- and 15-year property (furniture, appliances, flooring, the driveway, landscaping). With 100% bonus depreciation, her year-one deduction is roughly $137K. At 32%, that's about $38K more in her pocket this year than if she'd skipped the study.

"But year 2 is smaller." True. Her ongoing depreciation drops to about $13.6K a year. But that's not a loss. She already took those deductions, years or decades early. Would you rather have $38K today or a few thousand a year trickling in until 2050? Dana used hers toward the down payment on property #2.

"But I'll pay it back when I sell." Maybe some of it, and usually less than people fear:

• Recapture is based on what those items are worth when you sell, and 7-year-old furniture and flooring aren't worth much.

• A 1031 exchange can defer it.

• If you hold until you pass away, your heirs generally get a stepped-up basis, and the recapture disappears.

Even in the worst case, paying later with money that has been working for you for years usually beats paying now.

"But what if I can't use the whole loss this year?" Unused losses generally carry forward. They don't vanish.

The real risk is skipping the study. Here's the part that surprises people: if you bought a property years ago and never did a study, you can often do a look-back study now. It catches up all the missed depreciation in the current year without amending past returns.

If you've been sitting on a property, the opportunity is probably still there.

The one honest caveat: cost seg works best when you can actually use the losses, so loop in your CPA on how it fits your situation. For most investors buying or holding a decent-sized property, the question isn't whether it's worth looking into, it's how much you're leaving on the table without it.

For those who've done a study: what did it free up for you? And if you haven't, what's been holding you back?

(General education, not tax advice. Run your numbers with your CPA.)