I have tried a couple of times to cut my own hair and I stink at it!
This last time I cut bangs. Well let say this; I WILL NEVER cut my own hair again.
I still voted trimming split ends. I do that some times. Here and there. (hehe) More or less just remove the damaged ends from old highlights. When I have gotten rid of all of that I don't think I will do it any more.
I am impressed with people that manage cutting their own hair and it comes out nice. I wish I could do it.