I've had my Dinc2 for only a week but I'm glad that I started out with the realization that I need to add protection to this expensive little thing.
I got an Otterbox Commuter -- it's very well designed. The on/off and volume control switches work better with the case than without. The audio and micro-usb ports are covered (with flaps for easy access). The phone works very well with the case and I only need to remove it to take out the battery.
I also got a screen protector and a water-proof case (which is a compromise - the phone isn't fully functional in that case -- but offers excellent protection in wet weather.)
Considering the cost of replacing a Dinc2, it makes sense to invest in protection -- especially when the phone is fully functional in something like the Otterbox.