Being someone who tests and reviews a lot of smartwatches means I'm exposed to every company's take on tracking health and fitness. Whether it's Garmin's detailed performance and recovery tracking, Withings' whole-body health, or the Fitbit approach of making everything easy to digest. And, while there are definite benefits to every company's take, there's one third-party app and service that has completely changed my mindset and relationship with fitness for the better: Gentler Streak.