I base my policy on my food cost.
I usually let the crew make something small if they work a 5hrs shift, example a salad, breadsticks, or sub.
On the week-ends, we usually make a crew pie.
As long as the food cost stays at a respectable rate, I have no problem with rewarding my crew with a small meal. When my percentage goes up, the free small meals go away. If I have to take free meals away, I let them order something for 50% off with the exception of wings (always full price)
Anytime they order off the clock, they can pick up their pizza for 50% off.
My crew is pretty good as they will grab 10 minutes to eat if we are slow and they know when to get back to work. So they rarely break out. I guess that is just the benefit of having a veteran crew.