I am soooo old school that I soak my quilts in the bath tub with some quilt soap, rinse twice and drain in a plastic laundry basket..dry outside on a sunny day, with the backing side up..Of course this is a hand quilted queen quilt.
After 7 years she still looks very good .
As for some of my most used quilts I have not had any breaks in the seams.
I think it has to do with the stitch length,fabric weave and shrinkage of the fabric and a true 1/4 inch stitch.