I have a 4 month old Boxer puppy and we put her outside every hour and a half to go to the bathroom. She understands that when she is outside she goes to the bathroom then she scratches at the door to come in. The problem is she never goes to the door when she needs out, let alone barking or scratching. I've heard about using bells but I have 2 cats that might play with the bell instead of her using it to go outside. I don't know what to do and I was wondering if anybody had suggestions..

Both my puppies use to do that and once we got them a doggie door no more problems or accidents!

Doggy doors are great but make sure you can get one with a lockable latch. You don't want your dog going outside at night and waking up the neighbours :)

Mine don't really give me any indication that they need to go outside to do their business, I just make sure I let them out at regular intervals as you are doing.

As your puppy gets older you won't need to take him out as frequently as his little bladder will be big enough to hold it in for several hours.

Thank you for all suggestions!

No problem Chantal, I hope we helped :)