The NPD Group has an interesting chart on H2 2012 mobile accessory sales in the US-- one showing how mobile phone cases are #1 accessory on a dollar share basis during the period. 

Case market share in the US reaches 36%. Stereo headphones with microphones (34%) follow, together with headsets and handsfree kits (10%), batteries and chargers (10%), screen protectors (7%) and other accessories (4%). 

While the chart only covers the US market, we imagine it can apply at least roughly to our side of the pond...

According to the analyst US H2 2012 case sales are also up by 69% Y-o-Y, in a period where case average selling prices grew by 25% Y-o-Y. 

Why are cases so popular? Very simple-- smartphones. The slim, fragile designs and use of glass materials demands the safeguarding of such expensive devices. 

“Price holds less importance than protection on the list of purchase influencers, and consumer concern over the quality of materials indicates the performance of these accessories is more important than their aesthetics or cost,” the NPD remarks. 

A bit harder to explain is the popularity of headphones, whose growth reaching 67% Y-o-Y during H2 2012. After all, most high-end smartphones pack headphones. 

Then again, most customers also use smartphones as a portable media player replacement-- demanding the purchase of higher quality (and more expensive) headphones than the ones mobile devices tend to ship with. 

Go The Most Popular Mobile Phone Accessories (SAI Chart of the Day)

Go Consumers Spend More to Protect Their Expensive Investments in Smartphones (NPD)