The convention in this particular kindergarten is that for each meal there is one lunchbox. Meals are usually at 8-9 (optional meal), 11:30 and 14:30. My kids kids usually don't have the first lunchbox since they have just eaten breakfast a half hour to one hour before arriving at the kindergarten at around 8-8:30 and are therefore not hungry, but some kids in the kindergarten is there from around 7-8 to 16-17: and thus packs three lunch boxes. Some actually arrive at 6 in the morning and thus eat 2-3 lunch boxes and a breakfast first thing when they arrive.