I learned to type on typewriters in the late 70s. I was thrown in a typing class in high-school and I thought to myself "this is a useless class, I'm NEVER going to ever need this". Turns out it was one of the best things I learned in high-school.

Anyway, I never used double spaces after periods. My typing teacher would always give me grief for it, but for whatever reason, I just never did it. As you can see, I still don't.