My internet connection with a Comcast cable modem service goes down daily for a period of about 5-10 minutes without explantion. There service always comes back, but is there any way to avoid this problem?

Have you asked them why this happens?
I didn't have the internet for the past month because mine was going out for hours and only staying on for two to five hours throughout the day. So I canceled them. All they did was keep sending someone out to change the modem. I am sure my problem was a loose outside wire that they didn't seem to want to take care of.