How old is too old to train or housebreak - really?

I housetrained a 7-1/2 year old Pekingese that came from a shelter (he was removed from his home because of neglect-he had lived his entire life in a bathroom). It wasn't to difficult, let him know that you're happy when he goes outside and that you don't like it when he goes inside. Used a crate and a leash to confine him while the training was taking place. As far as commands, he picked those up very easily.

Haven't had any experience with housebreaking older dogs, but my daughter had a friend when they were both 11, that trained her Dad's hunting dog (9 years old at the time) to a first place in her obedience class.

Even housebroken dogs can lose their house training as they get older, so I would be surprised if you could reliably housebreak a dog 10 or 15.

Any age they can BE housebroken with patience and consistently. Although it harder if the older dog has a medical probably such as age related urine leakage. Those ones can never be fully housebroken due to medical issues.

The oldest I've trained,is a 8 yr old rescue,I think it is easier than a puppy.The older ones are more focused and have a larger bladder capacity.

leash trained and crate trained a 9 year old bouv, their life expectancy is around 12 so thats a senior for sure

as long as the dog is still able to control his bowel and bladder, he is trainable. Just because he's old does not mean he's stupid.. and not all old dogs are incontinent either.