How much of an age gap should there be between two dogs?

With your first dog already house trained and responding reliably to basic commands, you can dedicate focused attention to a new puppy's early training without also managing two sets of accidents, chewing, and inconsistent responses at once. A settled first dog can even help by modeling calm behavior, since puppies often learn quickly by observing an older companion.

Bringing in a second puppy while the first is still young and boisterous itself can lead to both dogs reinforcing each other's excitable behavior, making training and calming either one down considerably harder. It also spreads your attention thin at a stage when both dogs individually need significant guidance.

A gap of several years can also work well, and some owners deliberately wait until their first dog is a calm, mature adult before adding a second, which often makes for the smoothest introduction of all, provided the older dog is generally sociable and welcoming toward other dogs.

An older dog that genuinely enjoys puppies and has a patient temperament will handle a new arrival more easily than one that is more easily overwhelmed, regardless of the specific age gap, so factor your first dog's individual tolerance into the timing decision as well.

There is no single perfect number, so treat this as general guidance to weigh against your specific dogs and household circumstances rather than a strict rule.