One Space between Sentences? Or Two?

What is your preference?  And if you’re a client and are now realizing that your website was built with two spaces and you’d prefer a single space between sentences, or vice-versa, please just send us an email so that we can make the necessary adjustments.  

Personally, I’m not sure which is better, I just enjoy watching people argue about it.  From my angle, this is a generational thing.  I attended grade school in the 90's and early 2000's and two spaces after a sentence was standard at the time.  

Articles:

• One space between each sentence, they said.  Science just proved them wrong.
• Two spaces after period are better than one, except maybe they aren’t, study finds.