My fascination with gadgets means I turn money into crap sometimes. I'm not a fan of stuff that doesn't work, so I hardly ever even try to use a guarantee...if I have something that doesn't work, chances aren't good that I'll want another one.
But my fitbit has been fun for me for about a year and a half. It has stopped holding a charge. I contacted them and found that their warranty is good for a year. So obviously $100 for a year and a half usage is reasonable to them but not to me. I'll keep using it until I have to stay connected to the base unit while it is plugged in to use it and then call it quits. I will not be replacing it.