I know guys who've been doing their own buzz cuts for years, and they look fine..it ain't rocket science...I know a few guys whose S.O. is quite skilled at cutting their hair for years and they look fine...
I also know a few who've been giving themselves "regular cuts" for years and quite a few more who are attempting it now, and I haven't seen a "selfie" haircut yet that makes me think that it's a good idea...
I'm 70 now, and fortunate that my hair is still pretty thick and full and grows quickly...I usually get a cut every 3 weeks, and I'm sure I'm going to be long overdue before I can see my regular stylist, but my wife likes it and tells me to just roll with it...