Slate cites a survey back in July that showed 40% of mobile phone users use a case for your phones. 40%!
Here's a brief history of mobile phone cases. In the mid '90s, cases were bringing in a 45% profit margin for manufacturers, and were made of leather and worn either on a belt or hanging from a purse or wrist.
When clamshells became popular in the early to mid 2000s, cases became more-or-less obsolete, as the keys and screen were on the inside of the phone instead of the concrete-shock-absorbing outside. But iPhones and other touchscreen phones make the need for a case more relevant for people who tend to drop their phones.
I'm of two opinions on this. The first is that I have never dropped my phone, or dropped it so badly that it actually broke. But I do know a lot of people who do, so it's hard for me to say that cases aren't necessary for them. So while I may hate cases and think they cover up the nice industrial design of whatever your phone is with an ugly, rubberised finish, it's necessary for people who smear their hands in butter before they take a call. [Slate]