I have not moved a frog on any of my planes since 1983, when I made my last purchase. All are around 1/16. I do have a wooden jack plane at around 1/8. There is a little bit to gain by having an adjustable mouth. A carpenter might want a little more opening for rough work, and there is a rather marginal benefit to having a mouth at 1/16 rather than 1/8 for fine work.