A crate, or, in other words, short-term close confinement, can be used to help dogs teach themselves two very important skills. The first is eliminating only when and where it is appropriate. The second skill is keeping out of trouble - behaving appropriately in the house. Without these two skills, a dog doesn't have much of a chance in this world.
When the crate is properly introduced using positive training methods, most dogs love their crates. Canines are den animals and a crate is a modern den - a dog's personal portable bedroom that he can retire to when he wants to escape from the trials and tribulations of toddlers and other torments. He can take it with him when he stays at boarding kennels, and when he travels with you and sleeps in hotels and motels.
A crate is inappropriate for long-term confinement. While some puppies are able to make it through an eight-hour stretch in a crate at night, you should be sleeping nearby and available to take your pup out if he tells you he needs to go.
During the day, a puppy should not be asked to stay in a crate longer than two to four hours at a time; an adult dog no more than six to eight hours. Longer than that and you risk forcing Buddy to eliminate in his crate, which is a very bad thing, since it breaks down his instinctive inhibitions against soiling his den.