A high-end OLED TV is not something you want to replace every three years. You buy one to serve as the centerpiece of your living room for seven or eight seasons, handling movie nights, long gaming sessions, and Sunday sports without the picture looking washed out. Getting the size and panel tech right the first time keeps you from spending twice.
The best time to buy is late January. TV manufacturers reveal their newest models at trade shows early in the month, which forces retailers to slash prices on existing stock right before the big game. That clearance cycle gives you the best price of the year on last year's top-rated displays.
Keep in mind that 18 months of zero interest is a hard deadline, not free money. If you have any balance remaining once the introductory period ends, the standard variable APR kicks in on whatever amount is left.