Always tip when picking up carry out. That is the guy who took your order while juggling three other calls. He put it together from the kitchen. He added all the silverware, condiments, and napkins. Then he checked it again to make sure it was right before you picked it up. And what’s more, servers make the bulk of their money on tips and usually they assign someone carry outs for the night, just like they do tables. So that means for that night you have a server making less than minimum wage, making far less in tips because lots of people don’t tip for carry out, and doing what is on many nights, the most demanding job in the place. Maybe you don’t need to tip 20%, but you always need to tip for carry out.