>>> (You're going to get a lot of old farts disagreeing with this advice, but don't listen to them.)

  "I used to be with 'it', but then they changed what 'it' was.
  Now what I'm with isn't 'it' anymore and what's 'it' seems weird and scary.

  It'll happen to you!"

seriously, it's not "being old farts", it's being reasonable with your eyes and your tools: while you may have 20/20 eyes, you will agree with me that viewing a diff of two columns of code at 10px fonts is not an happy thing to do, as the difference may be just a comma or a dot, and those on a 15" 4k monitor are about 0.3mm. And you cannot really view the whole columns without scrollbars or overflows if you set the font much bigger.