I have longish wavy hair, so it's nbd to cut it myself. I used to use the scissors that came with the hair cutting kit from Costco, but these are several zillion times better and easier: https://www.amazon.com/dp/B00KVYBY8M/ref=cm_sw_r_em_apan_glt_i_dl_HEKBZQCCR7YEZQ5W7526?
They, plus a slight lowering of standards, have saved me several hundred dollars in haircuts over the years.
This is adjustable and a pretty good deal. Japanese steel holds an edge a little longer so you get more cuts out of it. From what I've been told self sharpening is impossible without very sophisticated equipment