I was reading in a book today you should wash your batting prior to sewing. I have never done this, do you??

Once in a while depending on the finished look I want. But I don't actually "wash" it since it would turn into a giant cotton ball. I just soak it in hot water and spin it out and dry it.

I prewashed once, but I didn't really see much change other than the batting looked rougher and of course it was smaller. It was warm and natural and I used the regular wash/dry cycles.

i do because i do not like the puckered look in my quilts

I do preshrink batting for some projects where I do not want the puckered look. All battings are not created equal and some REALLY do not take well to the agitation with out the benifit of the quilting to stabilize them . Generally speaking those with a higher distance tolerance for quilting will fair better . In other words pick a batting that can be quilted 10 inches apart rather than one that requires quilting 2-4 inches apart.

how old was the book???
the batts on the market these days do not require- or recommend pre=washing-
raw batts- bought from a woolery- or other source require washing- but todays commercial batts do not

Thats a good point. The book was a 1999 edition