A couple of threads have gotten me wondering if people have other rules for mealtimes and what they are?

For example: Do you say grace or give thanks for a meal? What do you expect of your kids and at what kinds of ages? Do they have to sit at the table for the duration of a meal if they eat or not? Do you eat at a set time? Do you stop your kids from eating (for example you eat dinner at 6pm, so the kids don't eat after 4.30pm)?

Do you have any other rules or traditions?