Do you need a case for a smartphone?

I feel like it's a necessity if you are planning to resell it, cracks, dings, and scratches can decrease the resale value significantly; plus on some cheaper devices, once the screen is cracked, the screen dosen't even work anymore.

But I can understand not having one too, phone designers takes months-years designing the phone perfectly; while case manufacturers just take a couple days to a week making a case. A case just really takes away all of the designers work and throws it in the trash. If you have a small contract like a 6 month contract (yes, thats actually a real thing), then it makes sense, if you break your phone, just get a new one after 6 months.