Not to milk a dead horse or beat a dead cow or mix metaphors

but isn't there some kind of rule in the broadcast world where you can't play the same song more than once every 3 hours? I've heard this rule being applied on dreadful (I mean commercial) radio where you can set your watch by how often you hear particular songs.
I think 3 hours is way to short, you still might end up hearing it 3 times during your workday (more if you work crazy shifts like roger.lee) and at that point you just want to destroy the radio, espscially if it's a song you don't like in the first place.
Anyhow I agree with 24 hours between playings of the same song. What's odd is that I almost never hear Supper's Ready on the station. Whoever requests it daily must usually do it when I'm not listening.