"People write double spaced because they’re told that’s what professionals do."

I write double spaced because single spaced looks like a great lump of black squiggles.  The fact that there are more words on the page doesn't mean I can spot anything with more ease.  I like the idea of picking a style that suits whoever is writing, and it's good to point out that nothing must be done just because someone says so.   But I think it's a bit odd to believe that it's *only* old-fashionedness that supports double spacing.