Yes, I think you should. Double spacing after punctuation is a holdover from the days of typewriters. Computer fonts are designed to space appropriately without adding extra space in. When I get text from an outside source, the first thing I do is run that GREP to clean it up.
Normally, yes, it's a single space after punctuation including periods.
However, I was just working on a book which I set in the new Linotype
Fleishmann and the editor commented to increase the space after the
periods and several other punctuation marks, and I saw her point.
So, as usual, the eyes have it -- if the spacing looks too tight to you,
increase it (better to do so with extra kerning rather than with 2
spaces). But 99% of the time, a single, regular space after a period is
all that's needed.
I've had the same request for a certain font. I solved it with a GREP style, which set the horizontal scale of a space after the full stop to 133% (But I bet the net result is the same as with tracking or kerning.)
But didn't you have a dozen or more styles for the main text? So you had to add the GREP style to all those paragraph styles? A bit of a pain, no? -- unless you're very careful with your based-ons.
Such a wealth of information here on this forum. Thanks so much everyone; very much appreciated.
(you'll be pleased to know that I just went back and took out the second space that I'd added after the period, and before the word "Thanks"!)