I keep a diary of how many hours I sew. It's not so I can figure out how much a quilt is worth. In my case it is supposed to be an inspiration to me to do more each month. I was in a lot of pain and had surgery last year so I was unable to sew as much as I liked. I am feeling better now, but I just need motivation.
I may take some classes from a LQS or go to quilting meetings to get inspired. I didn't get out much last year. Prior to that, at one LQS, that moved to a different city, there used to have a BOTM meet that I loved to go to for the "show and tell".
I did find out by tracking hours that I spent about 60 making a double size pieced quilt. I only kept track of that one because it was an exchange for a wooden bowl and I wanted the information handy in case he asked. I tried to keep track of everything including shopping for the fabric, materials, etc.
I work slow, and enjoy the process, so no one would be able to judge how long it takes by me. The above quilt had 3-D elements and was quite a challenge, I don't think it would normally take anyone that long to make a quilt that size.