Watch Rascal Dog Litter Box (1970) : Full Movie Online Free Beofre you begin training your pet, please understand that every dog is unique and has its own personality. Some dogs or puppies may take instinctively to the litter box within a couple of days, for others it may take a while longer. On average, it takes about a week to complete training. Also be aware there are bound to be accidents during the initial training period.