If the channel is already in the YouTube Partner Program, you can start earning from day one.
Ensure the channel is a Brand Account , which allows for a clean ownership transfer between Google accounts without sharing passwords.
Use tools like OutlierKit to verify that subscriber growth is organic and not driven by bots. Request at least 12 months of AdSense revenue exports and check for any active copyright strikes.
Be wary of sellers who refuse to use escrow, demand cryptocurrency, or have channels where the traffic is concentrated on a single viral video.