But it can be much, much shorter. One of the biggest problems with Dune is that it can run for an hour and a half, or it can run for 6 hours.
I certainly wouldn't call this a problem, but it is a true statement. Everyone should be aware of this before starting play.
Dune lasts 1-15 turns and I've had games last anywhere from 2-15. It's difficult to put a time frame on it.