I have a full head of hair, it grows very thick. I always have a businesslike short back & sides but not too short on top so I can part it.
I find by starting with a number 6 on top, a number 4 a bit lower, and then a number 2 on the sideburns and low down, I can cut my hair just as well as the average barber. The trick is to *blend* when you move to shorter lengths, by slightly raising the device from the surface of the scalp as you are meeting the area with a longer length. I bought it due to Covid19 but have been so happy with the result I'll continue cutting my own hair in future. Used twice now.