As each quilt pattern is a bit different it can be tough to get a true measurement. I have done full bed size log cabins , 1.5 inch cut logs in 8 days but that included 1 1/2- 2 days of sorting scraps , ironing, starching, and cutting from very irregular scraps. That does not include quilting. Needless to say I must have been in the mood.
I do find that even for some of the more complicated patterns .. if I do not have it done in 6 -7 weeks , there is a good chance it will never be done. My threshold for working with the same textiles/pattern for more than several weeks can be a bit low, plus the motivation to move on to the next is pretty high.