Yes, we use a doggie door. It was our salvation! Millie was housebroken, but we were having to get up all the time to let her out. We were not sure if she wanted to go out, just because or because she really had to go potty. Plus when she was using the bells to ring to let us know she had to go out, she was ringing them all the time so she could get a treat.
It took almost a month to train Millie to use the doggie door. She was afraid of the flap. But once she got the hang of it, it just solidified her housebreaking and was just too convenient for all parties involved!
