Well I'll throw in how I do it. Since I appraise,restore, buy, sell and consign only antique quilts on ebay and on the web. It is usually a very individual case by case situation.
Restoration of a whole quilt-I provide the antique fabric from my time period antique stashes, I provide all the cotton thread and I charge by the square foot if a quilt is 6 feet by 6 feet I charge $20 x 36 which equals $720 which is about how much a well maintained 19th century quilt would cost
If I am only hand quilting say an old antiquefamily quilt top it is $10x36 which equals $360 about the going appraisal value of a newly quilted antique fabric quilt
If just the binding needs replacing on an antique quilt-once again my antique fabric,thread etc but I charge by the linear foot $20
I also advise clients if I am presented with a one patch in shreds that restoration for value is not worth it, I can restor it for sentimental purposes but the cost is the same
Now I didn't just come up with this out of thin air I got the idea from a girl friend who was raised in an Amish village and has left now. She's an excellent quilter and resides in upstate New York now. She said that when she was young about the age of 6-10 yrs old she would make quilts for the community and for sale and they charged $5 per amish yard of thread used on a quilt. Now, an amish yard is from the tip of your nose to the length of your extended arm to finger tips. We know that a 6 yr olds amish yard is smaller than an adults and that the amish make very tight little stitches. See the hitch here. More yards of thread,because its a short yard and tight stitches. Alot of thread went into the quilts she made as a child hence the higher price. Nowadays most amish quilts are designed and pieced by amish but then shipped to asian countries for the hand stitching to be done there and shipped back to be sold in Amish villages. This is how the overhead cost stays low.