Most dogs take to a crate. It is a den: a bedroom they can use when they want a safe place. Used well, it calms them and cuts down on chewing, barking, and housetraining mistakes.

A puppy should not be crated for more hours than its age in months, plus one. A 4-month-old stays in no longer than 5 hours. An adult depends on the dog. One that lived outside has never had to hold it, so start short. Older dogs and dogs with medical issues may only manage a short stretch.

The crate should be just large enough to stand, turn, and lie down. If you buy one for a puppy to grow into, block off the back and open the space as the dog grows. Exercise before and after a long crate stay, and leave a good chew inside. For the first nights, the crate in your bedroom is often best: the dog feels safer, and the house stays dry.

Never use the crate as punishment. The dog will learn to avoid it. Do not use it to park a puppy under 6 months out of trouble all day. Treat it as a playroom, with toys, a place the dog likes.

Start with the crate, and a blanket, in a central room. Introduce it after a walk, when the dog is tired. Keep the chews in the crate so it goes in and out on its own. Feed it there with the door open. If it hesitates, set the bowl just inside so the head is in and the body is out. If it will not approach, put a strong-smelling meal inside, shut the door, and let the dog smell it. It will usually ask to be let in.

Once it will go near the crate, toss in a few favorite treats and let it go in and come straight out. Do that three or four times. Then shut the door while it is in, pass a treat through the door, let it out, and ignore it for a few minutes. Next, shut the door and pass several treats through before you open it. After that, put a stuffed Kong in the crate — peanut butter, freeze-dried liver, or frozen food and honey, so it takes time — shut the door, and talk calmly.

If the dog whines, do not open the door until it is quiet. Letting it out while it fusses teaches it that fussing works. It needs to be quiet for a few minutes first.

Build up to 3 or 4 hours. A radio or television on a calm station helps when the dog is alone. Rotate toys so they stay interesting. Do not put papers in the crate. A dog will not want to relieve itself where it sleeps, and a blanket makes the point that this is home. In hot weather, keep the crate out of direct sun. Some dogs would rather lie on a cool floor.

Some dogs, often puppies, learn this in a day. Some take several days. A few take weeks. Once it is trained, you have a management tool for life. Do not ruin it by crating too long or using it as punishment. Reward the dog for going in so the response stays quick. Keep the “kennel up” cue light. Do not let anyone tease or punish the dog in the crate. Watch children on this.