After entering payment details (Stripe/PayPal), you received a license key. You pasted this into the Chrome extension popup. At this moment, your Chrome profile was blessed for life (of that version).
Here are some frequently asked questions about Video DownloadHelper: Video -2021- Downloadhelper Lifetime License For Chrome
In 2021, the developer (Invitro) offered two primary paid options for the Chrome extension: Here are some frequently asked questions about Video
A lifetime license typically covers use on all computers owned by the end-user with no time limits. How to Install and Activate on Chrome About Chrome licenses - Video DownloadHelper video editors grabbing stock footage
Yes—with caveats. If you understood that "Lifetime" meant "until the next major rewrite" and you were actively downloading content daily (e.g., video editors grabbing stock footage, academics recording live streams), the $39 was a reasonable cost for a tool that saved hours of manual sniffing.