Many people are under the false impression that you can only crate train puppies and they refrain from crate training older dogs as they think it is too difficult. There are also many people who think crate training is inhumane but done correctly this couldn't be further from the truth. Dog crates should never be used as a place to be sent when punished.
When dogs have been crate trained correctly they actually enjoy the security of having their own place to stay. Even at times when they are not expected to stay in the crate the dog will find comfort in it's own area of the home. Provided the crate is in a sheltered place and there is fresh water available they will be completely happy to have their own home.
Dogs often get possessive of their crate and other members of the family, children in particular, need to understand that this is the dogs special area that they must respect. The crate should always be kept clean and where possible the dog should have a favorite rug or blanket to sleep on in the crate.
The crate should always be made accessible for the dog with the door open when they aren't required to stay in the crate so they can feel free to come and go as they like and stay in the crate if they feel like resting at times other than those destined for the crate door to be closed.
Older dogs can find the crate a very secure place as they become less confident with themselves when getting older. If an older dog does have a mishap and urinate or soil their crate it is very important that it is cleaned immediately so they will continue to enjoy their space.