Many dog's front paws are larger than their back paws. By distributing Clawgs in packs of two, we are able to give your dog the best fit for all four paws. This may consist of two different sizes for one dog.
Some people's dogs may only need paw protection or grip for their front paws OR back paws. There are dogs that suffer from partial paralysis in their hind legs, which causes them to drag their paws a bit and it is difficult for them to grip. Those dogs may only need Clawgs for their back paws.
When travelling mountainous trails with my dog, I noticed that her front paw pads would often get scuffed up. She would get discolorations on her front paw pads that were pink or white rather than black and I could tell it was tender at those spots. This never happened to her back paws. My theory is that her front paws would get scuffed up when bracing herself while going downhill on rocky trails. I made paw-wear for her front paws but never really put them on her back paws.
It all depends on your dog and the places you go with your dog. If you are getting Clawgs for insulation from hot surfaces, you will of course need four Clawgs. We don't want to force people to buy more than they need and trust dog owners to do what's best for their dog.