How long will a high-end roto-molded cooler keep ice in 90°F heat?

Three to five days with block ice. Manufacturers claim 7+ days in ideal conditions (70°F, pre-chilled, never opened), but at 90°F with standard use, you get 3-5 days. Pre-chilling the cooler and using large block ice gets you closer to five days; cubes knock off a day. Plan for three, be happy with five.