How often do you all get Botox injections for your maintenance?

Lately, it feels like my jaw muscles are getting tight again, and wrinkles keep forming around my eyes, so I think it's time to get Botox. I got it on a whim the first time, but now that the effects are wearing off, I can definitely see my facial contours changing.

People usually say to get Botox every 3 to 6 months, but I'm worried that getting it too often might not be good. On the other hand, getting it after my muscles have fully recovered feels like a waste, so it's tricky to figure out the schedule.

Also, since it's been a while since I last got one, my memory of how painful the needle used to be is hazy, so I'm getting nervous for no reason. How often do you usually get Botox injections to maintain your routine?