Confirm the app actually sits under this account
The value of an account with an app lies in the app record inside it. Ask the seller to show the app in the App Store Connect app list live, not through screenshots or a store link. A store link proves the app exists, not that this account owns it. If the app arrived via App Transfer, ask when and how, since transfer rules and conditions follow Apple's current documentation.
App status decides whether it is worth buying
An app can be live, removed from sale, taken down, TestFlight-only or never submitted, and all of these get sold as having an app. Check the current version, the last update date and any open review feedback. A removed or long-dormant app should not be priced like a live one. If you want to inherit an existing listing, a live app with recent normal updates is the only case where that makes sense.
Bundle ID, name and in-app products are locked in
A Bundle ID cannot be changed after creation, so compare it against your own projects for conflicts or reuse needs. The app name can change with a new version, but in-app product IDs are permanent, and unused subscriptions or purchases become maintenance baggage. Go through Bundle ID, SKU, primary language, category and the in-app product list, and ask whether each fits your business.
Seller name and account type are shown to users
The seller name on the App Store is the individual's name for personal accounts and the legal entity name for organization accounts. Users see it every time they open the page, so confirm you can live with it. Also confirm account type and registration country, since these affect available regions, documentation requirements and how hard later changes are. Exact requirements depend on what Apple's developer pages say at the time.
Login control must genuinely transfer to you
Whether the account is usable depends on who controls the Apple ID email, phone number and two-factor devices. If those stay tied to the seller's devices or details that cannot be handed over, you have no stable control after delivery. Ask whether the login email can be handed over, how verification numbers are handled, and whether you reset credentials yourself afterward. Any arrangement that relies on the seller receiving your codes long term is an incomplete handover.
When to stop or switch plans
Pause if the seller cannot demo the backend, the app status contradicts the description, past rejections or takedowns are not disclosed, or only screenshots are offered. Review emails and Resolution Center records in App Store Connect are the main evidence of compliance risk. If your category or target regions differ a lot from the existing app, an aged account without an app may fit better, since you avoid inheriting irrelevant history.