I have strong opinions about how to knit socks so they fit. First of all, I like for socks to have a slight “negative ease”. Negative ease means the socks will stretch to fit the feet, and that the socks look smaller than the feet when they’re not being worn. If socks are larger than the feet they’re intended for (called “positive ease”), they’ll be floppy and your shoes will “eat” your socks. In my experience, socks with negative ease wear longer (or else my family is not hard on socks).
About heels, the heel encompasses 50% of the leg stitches, and the heel flap should be square before turning, as in the above sock. If the heel is not long enough (too flattishly rectangular, if you will, instead of square) the leg will begin to sag, and you’ll forever be pulling your socks up, and that’s a pain. I’ve noticed that the short row heel (the one without a flap, as shown in the entrelac sock below) is not a very deep heel and tends to pull down the back of the sock leg. Had I been a better photographer, and laid the heel flat, it would look short and insubstantial. But they’re in my daughter’s dorm room and out of reach for a better photo! 
Also, when I turn a heel, I try to get as many short rows after the heel flap as possible. It looks more foot-like. I’ll explain that in the Heel section of my sock patterns
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