Collars For Growing Pups
If you just got a newborn puppy or a small dog that’s still growing, you should consider choosing an adjustable collar with lots of notches. Make sure the collar fits snugly on the smaller end, and then you won’t have to spend on collars for a long time.
Leave Space For Fur

When buying a collar, your dog’s fur needs to be taken into account as well. Dogs with thick fur and long hair need adjustable collars. Measure your dog’s neck before and after getting a trim, and then buy one that fits both measurements and can be adjusted. That way, no matter how long the fur is, the collar will fit.
Buy A Suitably Wide Collar

You need to consider the width and thickness of the collar as well. For larger breeds, wider and thicker options are suitable to provide support. For smaller dogs, those can be heavy, so buy lighter and thinner collars. If you’re unsure what width to go with, a standard one and a half inches wide collar will work just fine.
Examine The Collar Regularly

It’s not all to buy a good collar; you should frequently check if it fits the dog well. For a small breed, you should be able to put a finger under it. For medium and large dogs, two and three fingers, respectively.
Conclusion
Buy a collar that fits well and leaves room for some movement and easy breathing. You can refer to dog collar size charts for reference too. If you still have confusion, visit a veterinarian to make sure.
