I do both .... some quilts "demand" a one fabric backing and others "want" for a pieced backing. Also, if I'm sending for hand quilting, the backing will be with as few seams as possible .... one fabric, or possibly minimally pieced (as in inserting one block or similar.
A one fabric back, can sometimes give you a nicer look at the quilting or the benefits of a second whole cloth quilt. At Christmas, I flipped one quilt to the back that had a black/gold print. Then laid a Christmas lap quilt on top ... showed it off better than it being on a couch in the family room! And can see doing the same for other seasonal quilts, rather than making a full bed quilt in the future.
Here's one with a pieced back .... it just seemed right!
Butterflies in My Garden .... The Front!
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Butterflies in My Garden .... The Backside!!
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