With one of the latest updates to my Nokia Lumia Icon, I now have a pedometer with me at all times and I don’t even have to carry a Fitbit! Newer Lumias have a motion sensor in them and one of the features is a step counter. (The steps show up in the Health and Fitness app.) You can also get some pretty cool data about your location and motion in the motion data settings section. WPCentral has a good rundown of the new features there.
As long as this doesn’t drain my battery too much, it makes a lot of sense to have it integrated into the phone. I almost always have it in my pocket anyway so why should I carry a separate device?