The tax mechanics of a 1031 exchange belong to your CPA and your qualified intermediary, and nothing here is tax advice. The underwriting mechanics belong to you, and they deserve their own page, because an exchange changes the buyer before it changes the numbers: it puts a clock on the search, and clocks make people pay for buildings what the deadline is worth rather than what the building is worth.
Name the pressure honestly. The identification and closing windows are short, unforgiving, and known to every listing broker you call, which shifts leverage before the first offer. The deferred tax sitting behind the exchange feels like found money, and found money buys marginal deals: the reasoning goes that even an average building beats writing the check to the government, which is exactly how average buildings get bought at above-average prices by people who underwrote better deals all year. The discipline that survives the clock is a single rule: underwrite every candidate as if there were no exchange, and let the tax deferral improve a deal that already stands, never rescue one that does not. A building that only makes sense because of the taxes it defers is a bad building with a good excuse.
The exchange also reaches into deal structure through the debt replacement requirement. Broadly, avoiding boot means the replacement property carries equal or greater value and the debt gets replaced in kind, which means the exchange, not the deal's own logic, may dictate the size of the loan you place. That constraint belongs in the model as a constraint: the capital stack you underwrite should be the one the exchange permits, and if the deal only pencils at a leverage the exchange math will not allow, you have learned something important early instead of expensively late.
Timing risk deserves its own line in the plan. An exchange buyer has less room to walk from diligence surprises, less leverage to retrade honestly discovered problems, and a strong incentive to identify backup properties rather than one perfect target. All of that is underwriting context: the option value you normally hold as a buyer is partially spent, and the price you offer should reflect that you are the one at the table who cannot leave slowly.
Where speed helps rather than corrupts: being able to underwrite candidates fast and deep at the same time is the one legitimate advantage available under the clock. PropCalc™ exists for exactly that combination, full lease-level modeling in the time the deadline allows, and it carries after-tax and 1031 analysis alongside the deal so the exchange math and the property math stay in the same view without pretending to be each other. The clock will pressure you regardless. It does not have to pressure the model.