I usually buy a minimum of two skeins of each color when I make an order. I always have enough to make an extra pair, if one pair sells quickly or another size is requested, without having to reorder. That logic has worked out well for me over the years, but it's also resulted in stagnant skeins of accent colors. Usually, these are neutrals: grays, creams, tans, blacks, etc. Colors that work really well as a 'base' for stripe combinations.
It's nice to see the 10-20 yd scrap balls in my scrap bag being incorporated into new socks, and it's equally nice to see the neutrals being given a punch of color. I know lots of people like neutrals and single tones, but they don't inspire me like contrasts and complementing colors do. This has turned out to be a great, useful project.
Of course, now it looks like I'm crazy stripe lady!