I recentely had the problem, that a specific page was down, from which I needed a script. So I used my standard way to obtain this file and searched for this page on archive.org and found the page and the needed file.
So far for the background story.
I know answers should describe what a link contains in case it goes down. But this isn't always feasible and if we're linking to some sort of "personal" page, it's quite likely that the page will go down sooner or later.
In such cases usually the answer provides enough information to answer whatever the OP asked, but any visitor who has a similar question, which could be answered by the linked source, won't find his answer (well at least if he doesn't know the archive trick).
So now my question:
Should we mandate / encourage linking to archive.org versions of the linked sites (at least in answers)?