I wore a Fitbit for years. I lost about thirty pounds and really began to focus on things like heart rate etc... but then it started to fall apart. I had a charge HR and the bracelet around the display began to peel away. I had it replaced using their warranty. The new one did the same thing in half the time as the last. This time I was offered a discount on a new model. I didn't really want a new model (I'm cheap lol. The thing cost like $150) so I just took it off. I'm just 35 and I lift four days a week so I'm not real worried about gaining the weight back.
I guess long story short Fitbit is great tool to help you get in shape. They just don't last forever lol.