Use this technique to avoid estimating for a long tail cast on. You'll get the neat edge of the long-tail method without the fuss.

"No More Estimating Tail Length for a Long Tail CO – Cocoknits Use this technique to avoid estimating for a long tail cast on. You'll get the neat edge of the long-tail method without the fuss.", "Use 2 balls, slip knot both strands together, then do typical long tail cast on. Cut off one strand and begin work with the other. At end, slide slip knot off and pull to undo knot. 3 ends to work in, but no running out of yarn mid-cast-on.", "Requires two balls or skeins", "Not sure why this NEVER occurred to me", "Brilliant - and so obvious!"