Housebreaking is a major chore. Our puppy is almost 6 months old and still not fully housebroken. We are both retired and take her out all the time. My suggestion would be anytime you can't watch him put him in a crate. Take him out every hour maybe even more frequently around meal times. Also right after sleeping or lots of playing. Keep a log of when he goes and you will most likely see a routine develop.