I have a S&W 19-3 which has its gas ring on the yoke. This means that propellant residue and other crud can easily find its way inside the yoke barrel area and start to slow and even prevent the cylinder from spinning freely, meaning that I need to take the cylinder out of the frame and clean the yoke barrel fairly regularly, probably once every 100 rounds or so (when I really start to notice it).

With the gas ring on the cylinder, high-pressure propellant gases and residue escaping from the barrel-cylinder gap has a harder time of finding its way inside the cylinder, and so that area stays cleaner longer. I clean out that area maybe once every 1,000-1,500 rounds.

That actually was my reasoning for picking up my own 14-4--I'm planning on shooting it a lot, and I didn't want to be cleaning it that often.