As long as you deactivate the license before formatting, you can reactivate it on the fresh system. If you forget to deactivate, contact support to reset the key.
Typically, a Lifetime license includes updates for the current major version. Major version upgrades (e.g., v5 to v6) may require a discounted upgrade fee. Yt Saver License
Only if you purchased a multi-device license. Sharing a single-device license will cause deactivation conflicts. As long as you deactivate the license before