When you are going to adopt a puppy, ideally the right time to get them is at 7 weeks old. Puppies need the first 6-7 weeks with their mother and other puppies to learn how to be a dog. They then need to be introduced to people so they can bond with you, the owner, strongly. If you take them too early they aren’t well adjusted and ready and if you take them too late they won’t have as strong of a bond with you.
A piece of advice to anyone that is thinking about adopting a puppy is to prepare and be prepared to spend the first 3-4 months with them. I have had dogs that I didn’t train that well and I have had dogs that I trained better and spending that initial time with them is priceless. You have this pet that is now your friend and will do the things you need them to do and you get credit when your dog behaves. When you can get your dog to behave you enjoy them so much more. It is important to get your dog’s behavior under control early on to build the bond and make having a dog much more enjoyable.
With potty training, dogs will go through a regression that usually happens around 4 months old. You have been training them and it is going great and then all of a sudden it’s like they forgot everything. You almost have to start over by putting them back in their crate, limit their time out, and take them outside many times during the day. When you let them out and they go to the bathroom you can then trust them for only about 20 minutes afterward. They can be out in the house or in the room but you should be watching them constantly. You need to watch for signs such as sniffing a little too much or start going off into a corner, then you need to take them out and let them use the bathroom once again. It helps to be very consistent and repetitive with their bathroom routine because that is what helps your dog learn.
If you start training your dog with potty pads it is ok to eventually move them to going outside when they are older. In doing this you run the risk of your dog mistaking a t-shirt or anything on the floor as a potty pad and using it. The transition from potty pad to outside can be confusing for your dog and it is better to start with going outside if possible. In the end your dog is choosing their spot and the goal is for them to choose the spot that you picked for them.