If its not a golden rule it should be

Yes, we all get busy, but how hard is it to call someone back within 24 hours to get business?

Recently I called one golf course to talk to their course pro about golf lessons (I'm worse than this implies). So while I waited for him to call me back, I called another course and found out their pro was away until the next day.

After 24 hours I was on the phone with the pro who was away and booking an appointment. The other pro still hasn't called me--a week later. Even if he was the best teacher in the world I wouldn't take lessons from him because he's obviously is too important to call me back.

It doesn't matter now because someone else got my business and I can only guess others have followed suit.