I [Adrian Rogers] would say probably eight hours on a sermon from scratch. Sometimes you may spend an hour, sometimes you may spend three weeks. It depends on the subject. Like one man said, "How long did it take you to prepare that sermon?" He said, "40 years."
Some things come together in a hurry, some things don't. A lot of it depends on my own schedule. I could just spend more and more time, getting deeper and deeper, and nuance-ing it a little bit more, but you don't always have that privilege.
This question and answer came from a Doctoral Colloquium session with Adrian Rogers and several Doctoral Preaching candidates in 1997.