I was always taught to type two spaces after a period. Perhaps this was because when I learned how to type, I learned on a typewriter not a computer.
I never knew there was a debate on this until today.
Apparently it is wrong to use double-spaces after periods because computers can now properly space letters and sentences. But, I fear that it has been a habit of over twenty years that I will not be able to break the habit. Anyway, I think it is easier to read when there are double-spaces. No one is grading my grammar anymore, so who cares?