My wallet is about 25mm thick. If a folding phone is going to reduce its width/length, I think I'd want the folded thickness to be around the same as my wallet

My wallet is about 25mm thick. If a folding phone is going to reduce its width/length, I think I'd want the folded thickness to be around the same as my wallet so I can stack them in my pocket without one slipping past the other. This is how I used to carry my flip-phones, which were around that thickness which closed.