Linda, I don't quilt for others, but if I did I would certainly charge by the hour. If you are accomplished at SID and using your ruler then it really speed things up. If you are not good at SID; you will be when you are done with a couple quilts. I, for one, would pay for SID because it makes everything neat and tidy with no wobbly seams. It's worth it in the end; and I've already expended a lot of money and, especially time, in piecing the quilt top. If you show examples to your clients they will be more willing to pay for it. Above all, never give your work away! I owned a quilt shop for 10 years way back and my father used to tell me "You are not Santa Clause, you don't give things away". LOL..... he was self employed his entire life and he knew!