Two spaces after the period . . .
. . was the norm for all typewritten correspondence and the full em space was used in printing. Having had both typing and printing classes in the 1957 - 1959 timespace I know this is what was taught.
Some time in the '60s this changed, probably because editors calculated how much column space could be saved by closing up the text. Now many word processors can't even handle a two space stop properly.
That other thing is caused by people trying to do things "right" without the propper characters available. The start quote and end quote are different characters in the type case but on the keyboard they have both been replaced by the vertical version used for both start and stop.
