A: Hello missR, Yes, you can use the license code whenever you want. Though you will see a notice to activate the software within 60 days from AppSumo, the license is actually valid for lifetime.
If you reinstall your computer or get a new one, you can also contact us to reset your license code. Don't need to worry about the activation issue.
Let me know if you have any more questions.

PS. You can also download and install the video downloader from our website to test it before making a purchase.