A double bed quilt quilted with a very simple edge to edge design could take from 2 to 6 hours to quilt. As you can see that is a lot of varience. Then there is the fact that it would also depend how much time the quilter spent per day quilting (1 hour, 3 hours?). And, just how big was the double bed quilt? Some people call a king size a double bed size. Then if there were health or injuries problems that came up, that could add more time. Just keep the communication between your quilter and yourself open. Check on it regularly.