One of my best habits in 2 decades DJing has been to record every time I mix, whether at home, at a great gig or a so-so one.
Recording your practice allows you to listen back and see what worked and didn’t work as well as really hear what your tracks sound like at different speeds than they were recorded at…
Recording your live sets allows you to capture them all, you never really know when magic is going to happen and you don’t want to be stuck wishing you recorded after the fact. You can always crap a recording you don’t like.
One thing you should not do is rely on promoters to record. Some of them will accomplish this and get you a quality recording in timely fashion, but it is definitely the exception, not the norm.
Spend $150 on your own recorder and 32gb card, take it with you everywhere, if there is a recorder plugged in at your gig try to find another out to record on your own. Cause even if there is a quality recording made at your gig who’s to say when you will get your hands on it?
When you make your own recording you get to listen on the drive home, a little joy I’ve gotten used to over the years and especially nice when the drive is long.