Keep the wet stuff out of the sandwich and the dressing off the lettuce.

If you want both a sandwich and a side salad to survive until lunch, you have to keep moisture away from the bread and the greens.

The enemy isn’t time — it’s water. A sandwich gets soggy because wet ingredients soak into the bread. So either use a barrier, or keep the wet things separate. Toast the bread, spread mayo on both inner faces (a thin layer of fat actually helps), and put tomato or pickles between the cheese and meat, not right against the bread. The best move is packing condiments in a tiny container and assembling at lunch. That also gives you a crunchy sandwich instead of a limp one.

For the salad, the lettuce wilts when it sits in its own water or in dressing. Dry your greens thoroughly (salad spinner or paper towel), and never mix dressing in ahead of time. Pack it in a small container or a little jar. Here’s the trick: throw a crumpled paper towel in with the lettuce — it soaks up the extra moisture that forms from being sealed in a box. Works all day.

You don’t need fancy compartmentalized lunch boxes. Just two small containers and a little bit of strategy.

Your lunch will taste like it was just made, not like a science experiment.