Whoa!

I don't wash 100% of the time
I always wash batik.
If I use red, black a lot of dark colors I will check to see if they are going to bleed.
I don't want to have a fabric in my quilt and bleed on other fabrics so better to be safe than sorry.

Wanda, I've never tried this method--it sounds great. Thanks for the idea!

i always wash material for anything

because I do not make wall hangings only, I prewash all my fabrics using quilt wash (ORVUS) soap and tumble dry medium. When I go to use the fabric, I sink-soak it w/ starch/water (25-40% starch) and spin it out before drying to damp stage. I now have crisp fabrics which take a press well. The starch can be "reactivated" with water spritz. No overspray in my sewing area, and fabrics are stabilized when needed. All this gives me the ability to do accurate cutting/sewing/quilting.

I guess I may be overly cautious, but I always wash my fabric first. I want to know what's going into my quilt before I begin. I don't have to worry about colors bleeding from one fabric to another (You can read all the horror stories here about that!), and the fabric will have done the majority of shrinking, so there won't be uneven puckering or shrinkage later. I know the fabric is truly clean, too. I even wash small pieces by placing them in a mesh bag to prevent unraveling and wadding up.

I always wash my fabric as that is how I was taugh.