;A fitness tracker helps you set simple goals and measure your progress toward them. You may want to take 8,000 steps per day, for example. Nearly all tracker units can help you figure out how close you come to this goal each day. If you have a more complex goal, such as preparing for a half-marathon, you’ll probably need a high-end fitness tracker paired with a smartphone app that specializes in running.;The newest Fitbit Versa models have built-in GPS to help with this.