I started with a 4/8 mainly because they were less expensive. I still have several in my rotation and enjoy using them. I find them especially handy when having to trim around my Van Dyke. If I am going somewhere special I'll dig out one of the two 3/8 that I have for very careful and close trimming. Draw backs of the smaller sizes, you have to wipe the blade more often. I haven't found that to really be a drawback because it gives me time to see how my shave is going, whether I need to re-lather and make sure I am concentrating on the shave. Every time my mind wanders I have a cut/weeper. 5/8 and 6/8 are the mainstays and a lot of shavers are Jones-ing on 7/8 and up, feeling the weight adds tot eh quality of the shave and don't have to wipe the blade as often. It really is a matter of personal preference at all times in the hobby/sport/necessity/what ever you want to call it daily event.