I'm well under 40, and happily use two spaces. I find it helps with clarity of reading for many fonts, and is worth the millisecond to double tap SPACE. BTW,

I'm well under 40, and happily use two spaces. I find it helps with clarity of reading for many fonts, and is worth the millisecond to double tap SPACE. BTW, I do this mostly from Emacs, while indenting with Tabs.