10 days is a bit long. think of how your body sweats each day. The most a base should be kept on is 7 days. I'm surprised you made it to 10 without having the seal start to come off or without a leak occurring. If the 2 piece is fitting fine and there are no leaks or skin irritation, I still would go no longer than 7 days...the same with the bag. Change them both at the same time so it's easier to keep track.
Earthgirl
~ileostomy since March 13~