When a business depends on custom software, spreadsheets, integrations, or one person who knows where everything lives, buyers often treat the seller's post-close availability as the safety net. That availability is the window for the handoff, not the handoff itself. Before close, I'd want five things for every workflow tied to revenue, delivery, or compliance:1. A named operator and a backup.2. Admin access the company controls, not the seller's or a contractor's personal account.3. Where the source code, data, documentation, and backups live.4. Evidence that licenses, vendor accounts, and IP can transfer.5. One live handoff test, like restoring a backup or deploying a small change without the departing person.If one of those fails, that doesn't kill the deal by itself. You handle it in the terms instead: closing conditions, what the seller owes during the transition, the size of the escrow or holdback, and the budget for the first 100 days.Instead of asking whether the seller will stay for 90 days, ask what has to be true on day 91 for the business to keep running without them.