Great post — this is exactly the kind of clarity people need around cost segregation.It’s really important to educate folks that not all properties are eligible.

Say I pick up a 25-year-old rental for $300k—under the 2025 law, how much of that can I deduct right away with bonus depreciation?

One of my favorite deductions to see for short-term rental owners is land improvements.Land improvements can make an STR significantly more marketable.

You're looking for validation of your determination to deduct it, the rules be damned. 

Essentially you are plugging in all of your data and they are using market price studied to generate your deductions.

I have a W2 job to deduct losses against and I'm hoping my AGI should fall right around $100k including the losses from my Schedule C (side business). 

So this sounds like a $10k depreciation deduction per year.

If you buy appliances and furniture for this property, the cost is always deductible, and you do not need cost segregation for that.

If you are eligible for a home office deduction, any increase in audit risk should not deter you from taking the deduction.

The STR portion can qualify for a bonus if you materially participate; however, the LTR units usually won’t, as this is where a properly scoped cost segregation and a quick free estimate of benefits upfront really help clarify what’s actually deductible before you commit.Glad to help when needed.