I always pack up at night

Day care has fridge and microwave, so it works for any cooked food.
My daughter's bento box has two layers, one is for fruit and snack so it doesn't need be warmed up.
My husband's bento box is the same, just bigger.
We put lots of grapes, raspberries, cherry tomatoes and strawberries on top, other stuff like burritos and chicken at bottom.