I work a 40 hour a week job and have 3 kids under 9, one of them with disabilities. I only have 2 days off a week and I try to dedicate some of them to stitching. Because one of my sons is very "time" oriented, we have scheduled my stitching time into our activity schedule. I can take anywhere from 4-6 hours a day, with breaks, to stitch the 2 days I have off. I can get a lot done, at first it was very robotic and I had to come up with things to do to fill my sewing time, but within a couple weeks I was used to it and I can get a TON done. With that schedule, I cranked out 14 quilts last year.
That's just machine time. During the week, after the boys are in bed, I hand quilt in front of the tv, or do some type of handwork, for an hour or two to relax before I go to bed.