Great story. I laughed so hard I started snorting. Glad to see curie picked you up!
I also embraced my destiny some years ago and bought some clippers for less than the price of a womans haircut. My wife then got once chance - which she blew for trying to shear me like a sheep - and I've been doing it myself ever since.
I have on rare occasion sought out a barber if I needed a formal cut (maybe 4 times in the last 10 years) but the risk of getting caught between a barber that's too chatty or charging womens prices is quite the vice.
How do you avoid missing spots at the back?
As you say yourself "...shaving a head isn’t the most precise of procedures."
When shaving I find it easier to feel rather than see what I'm doing but I do use a couple of mirrors. I do also let the missus check and tell me if/when I've missed a spot, but I can do that without letting her get hold of the clippers ;)