How much ice should I buy for a 50-quart cooler for a day trip?

Start with two 7-pound bags (14 pounds total) — that’s the sweet spot for a full day at the beach. You want a 2:1 ratio of ice to food if you’re keeping drinks cold and opening the cooler a lot. Pre-chill everything the night before, and drain the water as it melts to keep ice until sunset. One bag is optimistic, three is overkill, two is just right.