I cut my hair this weekend. Usually I just trim it all to the same length, but I tried trimming the sides shorter than the top this time. It turned out fine. I was concerned that there would be an obvious, maybe irregular edge where the lengths changed, but I couldn’t tell at all. The longer guard was 7/8” and the shorter guard was 3/8”.

I went to a bit of effort to pin back the top of my hair (it hadn’t been cut since early fall), trim the sides, then unpin the remaining hair and trim it with a longer guard. Part way through I decided that I was making it more difficult than it needed to be, and I think I probably could have just used my hand as a guide and done as well.