After pondering this inponderable, I took my question to the second font of all knowledge, Google. (The first font of all knowledge is Wikipedia, where anyone can write anything and proclaim it so. I like it.) Google pointed me to the UK's Phrases.org, which says:
The stitch in time is simply the sewing up of a small hole in a piece of material and so saving the need for more stitching at a later date, when the hole has become larger. Clearly, the first users of this expression were referring to saving nine stitches...
The 'stitch in time' notion has been current in English for a very long time and is first recorded in Thomas Fuller's Gnomologia, Adagies and Proverbs, Wise Sentences and Witty Sayings, Ancient and Modern, Foreign and British, 1732:
Fuller, who recorded a large number of the early proverbs in the language, wrote a little explanatory preamble to this one:Isn't that fabulous? I writer in me loves the "clinking of syllables" and "many a little will make a mickle." What's a mickle? Apparently it means "a large amount."
"Because verses are easier got by heart, and stick faster in the memory than prose; and because ordinary people use to be much taken with the clinking of syllables; many of our proverbs are so formed, and very often put into false rhymes; as, a stitch in time, may save nine; many a little will make a mickle. This little artiface, I imagine, was contrived purposely to make the sense abide the longer in the memory, by reason of its oddness and archness."
This makes a great segue to my mickle of a Diamond Yoke Cardigan. As you can see, I've finished the body and am almost done with the second sleeve. Next I will be putting all the stitches on a very long needle and commence knitting the yoke.
The Brits are right: many a little makes a mickle indeed! Soon my mickle will blossom into a muckle - which is just a whole lot of mickle. Little to mickle to muckle? No matter. I'll just be glad to finish my sweater.