Buy a cooler, not a lunch box

If you work outside with no fridge or microwave, the best lunch box is a soft-sided insulated cooler with a leakproof liner and a good ice pack.

A normal lunch bag or paper sack won’t cut it. You need real insulation and a liner that can handle melted ice. The good news: you don’t need a $200 Yeti. The Ozark Trail and RTIC soft coolers do the job for a fraction of the price. Just make sure the zipper feels sturdy and the inside wipes clean, because it will get gross.

The ice pack matters more than the bag. Use two — one under the food, one on top — and keep the whole thing in the shade if you can. Even better: freeze a couple of water bottles instead of ice packs. They keep everything cold and you get cold water by noon.

For hot food, skip the insulated bag entirely and get a wide-mouth vacuum thermos. Stanley, Hydro Flask, or even the old Thermos brand all work. The trick is to fill it with boiling water, let it sit five minutes, dump it, then pack your food. A stew or pasta will still be steaming at lunchtime.

Cold sandwiches and salads are easy. Anything warm means a thermos. That’s the whole system.