Should you cut down your Winter Iris leaves or should you let the leaves die back as you do with daffodils?

I have a couple types of iris plants and I either cut them back as they start to die in the fall or just wait and mow them over when they all have turned brown. In the spring they come back. Iris' are very strong and hard to kill. Good luck! I have read that you should let the leaves die down since all the nutrients will go back into the bulb for the winter. I usually wait until after a few good hard frosts here(Mn) and then the leaves can be easily (gently) pulled off. As with my other bulb plants, I have noticed that if I let them die down on their own, the leaves will turn brown and make their way to the bulb or tuber. This can and will introduce a fungus into the parent bulb and can make it decay. I have lost amaryllis, gladiolus and iris' this way. I trim my leaves and the flower stem back to a minimum after the last bloom falls if I am going to transfer them around the yard. If they are to stay in place and winter over, I keep the tips trimmed as they turn brown and remove this material from my beds as to not spread any disease. Yes they are hearty plants but I lost my only Purple bearded dragon to this bulb eating fungus.