call Roomba and let them know. it seems that they have updated their batteries and memory within the past year or so. They sent me a new battery and something to update the machine...can't remember what now.

Thanks, I will be in touch with them.

Mine goes until its wheels fill up with fuzz and then it asks me to "Clean Roomba's wheels." I do so and it goes merrily on its way. Several hours total. Our gameroom carpet is very difficult to vacuum; it has an extremely deep pile and pad and acts like Velcro to lint, animal hair, etc. In a perfect world, I'd tear it out, but it's in good shape, so I'll wait.