I'm still confused as to how much twist to use when plying my yarns?

I'm still confused as to how much twist to use when plying my yarns? I need some help with plying also. I've spun a fine singles, but find that I'm having trouble judging when I've put enough twist in when plying. I had to go back and add more twist after the first plying, and the yarn was nice and balanced until I washed it. I'll have to go back and add yet more twist to it. I know that when the singles sit for a few days, they don't act like they do when fresh, but I just can't judge what is enough twist in the ply. I reeeeeeaaaaly don't want to have to spin each skein two or three times! Help! A: As a teacher, that is the most frequently asked question. And the easiest answer is often to just ply it until it looks really good with the "pearls" or "bumps" nice and distinct and plump. They look dead when they are underplied and flat when the yarn is over plied. Another way is to take off a length of the old single, where you know it hasn't lost any twist. Tie the two ends together in an overhand knot. Then put it into hot water, actually any water will work, hot is just faster. It will immediately ply itself up to where it needs to be. Take it out of the water, shake it and let it dry. Then you can ply to match that little plied sample. If a skein is still twisty, (more than one or two twists, after washing, and snapping a few times), the direction the skein is twisting, is the direction you need to add to the skein. In other words, if the whole skein twists on itself in the S direction then it needs more S twist. Conversely if it twists on itself in the Z direction then it needs more Z twist. I put it on my swift while it is wet and then just run it back through the wheel in the correct direction, checking to see how well it is doing by hanging down a long loop. It often doesn't need very much correction. Or it only needs correction in certain parts. You can also save a great deal of trouble if you save a self-plied 8 or 10 inch length that you allow to ply on itself while you are first spinning the single. I hope this helps.