On my walks yesterday and today my Blaze has shorted me in the neighborhood of 3000 steps on each day. I know this because I walk the very same routes regularly. Yesterday's route, the norm is 16k to 17k steps. It only gave me a 13k step reading. Today's route, the norm is 12k steps, it gave a reading of less than 10k. It's been doing this at least one day a week for the past couple of months and it's quite annoying. And before you respond back with suggestions of what I might be doing to cause these fluctuations, I live in Southern California, so I'm not walking with my hands in my pockets to keep them warm. I always wear the Blaze in the same spot on my dominant wrist. This is a Fitbit software issue, it's not my fault.
