The Charge HR can collect dead skin in the well where the charger connect. I use the hard corner of a towel to clean it out every so often.
When my first FitBit died I didn't contact them until 4 days after the year warranty was up and I got a 50% offer off a new Fitbit. Over a year later I was gifted a second FitBit and the band broke within 6 months. They mailed a new one without a receipt, but they did grill me about how I used it, if I shower with it, what kind of exercise I do with it on, if it's humid where I live, if I sweat a lot. When this replacement also breaks I won't be buying another FitBit. I've heard of other's getting the 25% offer, but I happen to know that the one I have was more than 25% off on black Friday. If you read reviews almost every one praises them for replacing units that broken within a year. I feel that you're actually paying twice as much to cover the fact that most of their products end up getting replaced.