It needs to be give and take on both sides, I went back to finish a presentation deck last night until 1am but I'll finish early in Friday or take time when it

It needs to be give and take on both sides, I went back to finish a presentation deck last night until 1am but I'll finish early in Friday or take time when it suits me and I don't have to tell my manager. One of the my direct reports took some time this morning to go do some person errands, didn't use vacation as he steps up when needed. He sent me a courtesy message to say he would be out for a few hours but it wasn't for approval. He gives when he needs to and he takes when he needs to and I trust him to manage that. But trust is needed and I've seen plenty of managers abuse people's goodwill, I can see why unions formalize that in a way.