I don't ever use the numpad, and the function row not very frequently, but I still use all the different sizes. It may have something to do with the way that I type, but I never use my pinkies for actual typing, just hitting shift and enter, so my pinkies are almost resting outside the mods sometimes, and my thumbs feel comfortable resting on the bezel below the spacebar when typing, so I use fullsize or TKL primarily for typing and 60% for gaming and casual use