Let's say we're at lunch. I ask what my share of the bill is. You say "Don't worry. I'm going to expense this. Our conversation was really useful for my project."
Or let's say three of us are working on a project due at 3 pm. It's noon and we're all hungry but we don't have time to go anywhere. I say I'm going to order pizza for us. You say "Make sure you expense it. Jim was already going