I didn't exactly plan it, so I guess I'm lucky in that I've saved (more like being lazy and not throwing them away) almost all of my old mix tapes - my own production and especially the ones friends recorded. Even if the music can be pretty outdated it is still nice to have documented the music I listened to back in the vinyl years.
Mix tapes took absolutely forever to produce,
at least a couple of hours per tape.
Sometimes it took a whole day, because you felt you had
to go through all of your 12" to find just the right ones!
With CD-Rs and mp3s the production is a bit faster but actually not that much.
The first copy still takes at least an hour or two:
you have to find the right set of songs,
maybe start with an overall theme for the whole compilation,
arranging the songs in the right order and
to write some liner notes... maybe do a proper cover too.
Ok, not all of my compilations get this thorough treatment.
Here's my "olympic" comp, with a cover image from Athens.
MP3 sound bite (5 MB). 20 seconds from each song.