I have Charter too. At least once a week, every week over the past 5 years I get a connection interruption that lasts anywhere from 2 minutes to 2 hours. Sometimes it's the middle of the week, sometimes it's Saturday afternoon.
I will say this though, the last time we had to call them in, they put a signal booster in the house right where the main line comes in and after I upgraded my internet speed thus getting a brand new modem that complies with the new high speed standards, I've had fewer interruptions and none more than 5 minutes. The last major issue we had came from a box 2 blocks away and was caused by a tech doing a new install on a house, the dipstick knocked out a 5 block radius. It took me 2 hours of arguing with their support to get them to not only admit there was a problem but send someone out to fix it.