I thought it would be fun to log all the live shows I've attended across opera, ballet, musicals, stage plays, talks, and concerts of both classical and modern eras, so... why not? :-)
I take a lot of the set lists (and accordingly, the duration of the set) from setlist.fm -- or from the programme from each show's respective webpage.
When I have covered the costs of a ticket for someone, I save the ticket price for both, so I have more legitimate analytics for myself.