Question: how long to leave a 4 month old puppy alone?
Answer: 3-6 months: At this point, consider the 1 hour per month rule. 3 month old puppies can wait for 3 hours, 4 month old puppies for 4 hours, and so on. After 6 months: An older puppy, like most adult dogs, has the ability to hold it in for up to six hours.