Gah. Size 10? Not for me. I always have to go up at least a size, because I knit tight, but I also like to work with thinner yarns. For worsted I'd probably be working on maybe size 7? Most of the time I'm working with size 2.5.

I do have a project where I'm working in size 10.5 (and I should get back to it) but that's for a lacy cotton throw, not a sweater.