It is crucial to the future of any dog that you get them housetrained. Many times, owners who don’t succeed with potty training give up their dogs to shelters. This is very stressful for the dog, and all too often means they will not live much longer.
The reason the methods are different is that with a young puppy it is a matter of their bodies maturing and of their understanding what you want. Taking them to their potty area every time they wake up is the single most important thing you can do.
But with older puppies and dogs, they have learned some habits that you need to get them to unlearn. Their bodies are almost always capable of holding it, but somehow they haven’t gotten the idea of where to go. You won’t need to get up in the middle of the night as you may have done with a young puppy, but you will need to be extremely vigilant. Crating the dog may work when you are not home, and tying the dog to your slacks with a long lead is a good way to make sure it doesn’t wander into the living room and use the carpet while you are concentrated on your computer in another room!
Here is an audio file about housetraining dogs that I made:
and another where I answer some questions about it: