Create one property file
A listing can introduce an opportunity, but it cannot establish the full investment case. Start a property file with the address, parcel identifier, ownership information, stated unit count, asking price, and the intended rental use. Keep the date and source of each document. Mark an unanswered question as unknown instead of filling it with an optimistic assumption.
Separate seller-provided statements from records you have independently checked. A simple evidence log can contain four columns: claim, supporting document, remaining question, and person responsible for resolving it. That makes the next conversation with an agent, inspector, lender, or local office more productive.
Check the income story
For an occupied rental, request the leases, current rent roll, payment history, deposits, concessions, and details of who pays each utility. Reconcile the rent roll with the documents available to you. Identify lease expiry dates and any difference between scheduled rent and money actually collected.
For a vacant unit, gather current comparable properties with similar size, condition, location, and terms. Asking rent is evidence of an offer, not proof of a signed lease. Track concessions and time on market where you can verify them. Keep projected rent separate from documented existing income.
Inspect the asset and the intended use
Arrange an appropriate inspection and obtain estimates for the issues it identifies. Record the condition and likely replacement needs of the roof, mechanical systems, plumbing, electrical systems, and other major components. Ask for available repair invoices, permits, warranties, and disclosure documents rather than treating a cosmetic renovation as evidence about the whole building.
Confirm the proposed use and unit configuration with the relevant local authorities. Review available title, access, easement, association, and utility information with qualified professionals. For flood screening, consult FEMA information and local records; being outside a mapped high-risk area does not establish that a property cannot flood.
Replace expense guesses with evidence
Collect property-tax records, insurance quotes for the intended use, utility bills, association charges, management proposals, and maintenance history. Check the assumptions behind a quote and whether costs may change after purchase. Distinguish ongoing operations, immediate repairs, and longer-term replacements so that one expense is neither missed nor counted twice.
IRS Publication 527 identifies common rental expense categories and distinguishes repairs from improvements for tax purposes. Use it to help organize questions for a tax professional; a cash-flow budget and a tax calculation are different documents.
- List which costs are verified, estimated, or still missing.
- Set aside a separately identified replacement reserve.
- Record the cash needed before rental income begins.
Close the financing and decision gaps
Obtain financing terms appropriate to the transaction. Record principal and interest, fees, amortization, maturity, rate adjustments, and any proposed refinance assumption. CFPB's Loan Estimate explainer is a useful introduction to payment and closing-cost categories, although the financing documents offered will depend on the loan.
Before making a decision, revisit every unresolved item that could materially change income, costs, timing, or permitted use. Assign a next action and a date. The goal is a reviewable set of evidence and assumptions, not a checklist with every box marked complete.
Turn the reading into a working file.
Use the interactive tools to keep your assumptions and evidence together.
Open due-diligence notebook ↗Find official research sources ↗Try the offer-price calculator ↗Sources & further reading
Public sources reviewed September 5, 2026. Definitions and publication dates can change; inspect the original material when using it in your own research.