In the event that you have Link Expiry setup and send out an email, the links in the email are set to expire after a set amount of time (let us say 12 months).

If you then wanted to send another email containing the same links, then the link expiry time would be set to 12 months from the time of the latest send.

So, if you copy an old email that was sent 11 months ago, and resend it, the expiry date of the links in the newly-sent email will be updated to 12 months after the new sent date.

For more information on Link Expiry, see this article:

https://support.vutu.re/hc/en-us/articles/360020560657-Set-Vuture-links-to-expire-automatically