A good fitness watch tracks your heart rate, sleep, and workouts without dying halfway through a long run. You want something built to last a few years so you are not replacing it every time a new model drops.
Timing is everything with tech. Watch for the brand's annual product refresh, because last year's model instantly drops in price even though it handles the exact same workouts you do.
That 18-month window is a hard deadline, not free money, so make sure the watch is paid off before the promo period ends or standard interest will hit the remaining balance.