Can puppies be left alone for 3 - 4 hours?

It's generally not advisable to leave puppies alone for 3 - 4 hours, especially when they're young. Puppies have frequent bathroom needs, and they can also get into mischief if left unsupervised for too long. For their well-being, it's best to come back home within about 2 hours when puppies are young. As puppies grow older and develop greater bladder control and independence, the amount of time you can leave them alone can gradually increase, but it's still important to ensure their needs are met and they're kept in a safe and stimulating environment.