I pre-rinse and hot dry the fabrics because the sizing really upsets my sinuses. I usually make a test block. I never ever cut out the whole quilt. There are times that I realize that I am no longer in love with the pattern and downsize from a queen to a throw. If the whole thing was cut out, I would feel like I had to finish it no matter how much I hated it.
I find I work best in blocks of production and time. Cut out for 10 blocks and sew them. Then go on to the next 10.
I rarely test for size since my blocks will all have the same seam allowances and therefore be the same(ish??) final size. The only time I become anal about it is if I am making a specific block or top for another person. Then everything goes under the microscope.
My time consuming downfall is choosing a colour palate. I can become paralyzed with indecision.