What I do is cut off all the leaves if they are big already. The next set is going to be smaller. Then as I think they're about to grow a new set, I cut all the leaves off again. Been doing this for about 4 years to a sago palm I received from an uncle who had been doing the same to it many many years before. Light exposure might have some effect, but mine has been in filtered sunlight a good part of the day. Also, mine is somewhat rootbound, but I think that might not be so necessary.