Ok, this may be a silly question, but I just have no idea! Say I wanted to make a simple seed stitch scarf for someone; how do I know how much yarn I need? I feel so silly asking this! I swear, it's probably something really obvious... thank you so much for your help!!
There is a little booklet you can buy called The Knitters Handy Guide to Yarn Requirements that gives estimates, you can also check out pattern sites like www.knittingpatterncentral.com and find similar patterns that use yarns in a similar gauge to yours for an idea.