if you have enough battery to get you through an entire day and have access to power for recharging at night, you've got the option to let it run or shut it off in between sets. based on your post i assume this is your situation. if so, play it by ear. you may end up doing a bit of both.
I haven't counted lately, but I'm working on my 40th music festival, so I'm experienced at power management. I don't like planning for a recharge during a festival so I have enough power for the whole weekend, but I take my rechargers just in case something happens, because rechargeables seem to go dead at the worst times! From personal experience, there's
NOTHING worse than being a taper at a festival without any battery power (or spare SD card space).
For this particular festival (All Good) I've figured out my power needs with enough conservatism that I should have enough power for the whole weekend. Unfortunately, I'm pushing the upper limit (if my conservatism assumptions don't pan out) and don't have alot of slack to use the set/forget method. I do like that method best though.
So, I'll probably do a combo of on-off and leave it running. Fortunately, the stages are side-by-side so there's not alot of running that needs to be done, but there's no doubt that forgetting to hit 'on' using the on/off method is a concern and a lesson from past fests.