I never pre-wash. However I just finished a quilt and washed it to get the "look" and also wash away the marking lines. The fabric changed colors. So perhaps pre-washing is a good idea.

I started as a garment maker, too so I wash everything. I am about to start on two different quilts- all kaffee fassett fabrics. One is several techniques- foundation pieced, english paper pieced, and appliqued. The other is raw edged appliqued. I had yardage, the 6" rolls, fat quarters and layer cakes. I serged them all except the layer cakes since they were pinked. the layer cakes shrunk every which way! some were fine but others were a good inch in one direction and others the other direction. I always serge the edges first so I don't lose any yardage- it takes a few minutes, but it keeps it beautiful! When raw edge appliqueing they say the chemicals on the fabric really make a difference in the way the fusible holds when using a light one like Misty fuse. Raw edge gives me the chills enough without asking for trouble!

I always prewash. I've had enough bleeders in my lifetime to understand the need. And if you swap fabric, it is a requirement.

If I don't prewash my fabrics I get itchy due to the chemicals and dyes used. I use a lot of batiks, they bleed dye and must be washed before using.
I sewed garments before I learned to quilt. I still make shirts for my DH and he asked if his shirt would shrink in the first wash. I said, no because the fabric was washed before it became a shirt. He was relieved that it wouldn't shrink.
Sharon in Texas

Usually I do, but not always. Cotton batting will shrink, so you'll get a certain amount of puckering in any case. I figure it goes with the territory, and anyway, the effect is soft and comfortable and tends to camouflage my booboos. I like to wash with Color Catchers so I can see what I might be up against.

I don't pre-wash and have never had any problems, even with reds and dark colors. Instead of color catchers I wash my quilts with Retayne the first time only. This sets the colors so there is no worry about future colors running. Retayne is used instead of detergent but only on the first wash. After that I use Woolite Dark and Downey on cold water & cool dryer. I would never wash my batting. I use Warm & Natural. I would end up with a pile of lint!

Well, I guess I'll "wade in" on this discussion. I DO prewash every piece of fabric BEFORE I add it to my stash. Reasons: (1) I have asthma, and it can get really bad. I don't like the coughing and struggling to breathe -- I use unscented shampoo, body lotions, etc. and I don't use any perfume or cologne -- I prefer to breathe and I don't like paying $40 for cough medicine ('cause it's not covered by insurance). (2) I've encountered far too many "bleeders" in fabrics, particularly reds, but also any brilliant color, so I test my fabrics for bleeding -- if the test is positive, I treat the fabric to "set" the dye, then wash, dry and press. (3) Shrinkage -- Cotton fabric will shrink some - so I wash not only the quilt top fabric, but also the backing. I generally use a very good polyester needle punch batting which can be quilted with quilting lines as much as 10 inches apart (I never quilt that loosely). (4) the chemicals used in fabric manufacturing can be very damaging -- my hands break out in a rash, and the finger tips split if I use unwashed fabric, so I stopped doing that years ago. The breathing issues and asthma are the primary reasons why I prewash -- asthma attacks can kill you, or at the very least cause you some real misery -- it's worth the effort to prewash. (5) The raveling for me is a non-issue -- I serge across the cut edges of the fabric before I load it in the washer -- it takes only a few seconds to 5 minutes generally and saves aggravation. I don't like the raveling and the tangles resulting from the raveling either. If you don't have a serger, zig-zag across the cut edges -- that will accomplish the same thing.

I prewash every thing. bought some this morning and it went straight into the washer and dryer. Took it out and folded immediately. Looks and folded great.

I wash, starch, and dry all fabric before it goes into my stash. I worked in a fabric store years ago, and you never know what customers have on their hands while they are looking at the fabric, or which bolts of materials the kids blew snot on while playing.

To me, ironing fabric and folding is relaxing and I enjoy a little break from the creative times of quilting. Plus, when I'm piecing, the fabric is already starched which helps stop a lot of the dirt from sticking. It also stiffens the seams while piecing.

I have not prewashed before but my DIL just sent me fabric (mostly batik and some bright pinks) along with the Mommy and Me quilt pattern for my new grand baby due in December so I am going to prewash her fabrics. Should I also prewash the batting?