Add an option to expire links, which are included in an email. Either via a option for the whole email or via the email editor in an extra property while inserting the link.
People who send emails with “time sensitive” links, like time based opt ins or offers etc.
If contacts click the link after a specific time period they get to an outdated/no more relevant page. The expiry option would add the opportunity to redirect the contacts to a specific page (with a hint, another offer, etc.)
When a user signs up for a newsletter they need to double opt-in. To comply with GDPR rules, user who don’t double opt-in need to be deleted after a while.
If the contact’s DB entry gets deleted, but the user who signed up clicks the link afterwards, they think, they successfully subscribed for the newsletter. You just lost a lead/contact.
A redirect to a specific sign-up landing page, which shows a hint (your link has expired; please sign up again) at the beginning would be nice—to give the user the possibility to sign up again.