I thought this would be overkill and I'd have empty spaces. HA.. apparently I have way too many cards because it's full. Because it holds so many cards, one side is for primary use , debit and bank cards. Then the other side for membership cards, Costco, Grocery store, and health insurance, prescription and such. Makes finding the right card easier. Of course I alphabetize my cards too. you may not be that obsessive with organization. Having one side that zips at the top and one that's open is a nice option. Zippered side holds things that I carry all the time. Open side for daily receipts. I wouldn't recommend putting your cell phone in it because if you use the zippered side, it takes time to get the phone out when it's ringing. If you use the open side it could slip out. Neither side is large enough to accommodate a phone with a protective case. It's ok, I didn't buy it because of the phone anyway.