My wife's Android phone and my iPhone have built-in apps that monitor steps we take each day. It would be nice to participate in the rewards program without buying another device. In my case, I had a FitBit Charge HR. I had it about 4 months when the battery died. I tried repairing it, but a part fell off and not I can't recharge it. I spent $34 for the FitBit and another $18 for a battery and installation tool. So that is $52 for a device I cannot charge now. Data that would be the same but would be directly available from the phone.