Generally permission changes only occur when you've entered your password (loose rule of thumb). Is there something you're doing each day that requires you to enter a password? In particular, what third party apps do you use?
Nah, I mean I run it occasionally and sometimes that happens to be relatively soon after a reboot, yet it doesn't let out a peep. It doesn't repair or even notify me of any changes. Nevertheless, as you said, it's something that doesn't need to be run terribly often. After installing software and updates is about it IMO.
it's not necessary to run repair permissions everyday, but it's still a good habit, just in case. it only takes 30sec to 2 min depending on your machine.
i do it too, but i also run cron scripts pretty regularly too