A good fitness smartwatch should track your heart, map your runs, and last at least three to four years. Don't fall for the annual upgrade trap. September is the magic window because tech companies launch their newest watches, which immediately triggers deep discounts on the previous year's models.
Last year's model still has almost all the features you actually use, but at a fraction of the cost. We can grab one for about $400 and split the bill over a year and a half without paying a dime in interest.
Keep in mind that 0% interest is a ticking clock, not a discount. If you still have a balance on your card after the 18-month window closes, the regular variable APR will hit your remaining balance, erasing all your savings.