Hyphens: Ur still doin it wrong
Q. Should "square foot" be hyphenated when used in front of a noun. For example "a 100 square-foot covered porch..." – from thornton, Pa. on Sat, Feb 21, 2015
Partially correct at best -- yes, "square foot" should be hyphenated, but AP style also says pretty clearly that compounds of numbers and dimensions are hyphenated before nouns they modify. If you should hyphenate "the 5-foot-6-inch man" and "the 5-foot man" (pp. 76), you'd certainly want to hyphenate the whole of "100-square-foot covered porch." Why would the rule go away just because "square foot" is two words? After all, the "hyphens" entry itself says "use hyphens to link all the words in the compound except the adverb very and all adverbs that end in -ly" (p. 292).
"The fewer hyphens, the better" is the wrong way to go about setting up a rule. What you want is the right number of good hyphens and no bad hyphens. If that means you write "ice cream cone" on one page and "ice-cream-cone-shaped UFO" on another, fine. That's not inconsistent; it's consistent about avoiding foolish consistency.