My ATA has been up for periods of 16 days recently (that I have noticed, there may have been longer periods). Right now it's 9 days 11 hours. When I first got it it would reboot every 45 minutes like clockwork and drove me nuts because all my phone indicator lights all around the house would flash bright red with each reboot but support fixed that.

Maybe once a week would be a good compromise or even every day if it was done at 2 or 3AM and not during the middle of the day.