Buy two 7-pound bags of ice for a 50-quart cooler.

Start with two 7-pound bags (14 pounds total). That’s the sweet spot for a full day at the beach without overdoing it.

You want a 2:1 ratio of ice to food if you’re keeping drinks cold and opening the cooler a lot. 14 pounds fills that gap. Pre-chill everything the night before — warm cans will melt your ice in two hours. Drain the water as it melts and you’ll still have ice at sunset.

One bag is optimistic. Three is overkill. Two is the Goldilocks number for a day trip.