Because of their small size, guests like to nibble on cookies much like they do appetizers. Plus, they always like to take a few with them on their way out. The general rule of thumb is to have between 3-6 cookies available per person, which will vary depending on whether there will be other desserts and appetizers.lus, they always like to take a few with them on their way out. The general rule of thumb is to have between 3-6 cookies available per person, which will vary depending on whether there will be other desserts and appetizers.