I do not keep track of bobbin fills or time spent in the sewing process. I am a very slow quilter. I design most of my quilts in EQ7 and so use the date in the saved name of that quilt project. Then, once finished and the quilt is ready to mail, I take a digital snapshot of it and save that on my PC's hard drive; again with the date. With these two dates, I know roughly how many weeks/months it took to make the quilt. It does not at all tell me the effort involved though. Since I usually piece both the fronts and backs of my quilts they do take me a long time. I started a quilt back in November 2012 and I am still putting the borders on the pieced backing!