Welcome to the board, from Texas. I think this is a matter of preference and indoctrination.
I don't wash fabric before I use it. Probably because that is the way I was taught. The quilter who taught me, and then became a dear friend is a professional who has made commission quilts and has owned her own business doesn't and told me it wasn't necessary. With a few caveats. Most dyes today are much more stable than they used to be, and the fabric can safely be washed in cold water without any problems. The exceptions are the dark/deep browns and reds. Test them first. The second is that I am a "traditional" quilter, and really like the slightly puckered heirloom look. I have never had a problem with any of the quilts I've made, pretty much all of which have been washed on a semi-regular basis. If I were as talented as KLue, and made the kind of gorgeous art quilts she does, I would follow her directions.
Also, I've found that the sizing in the fabric helps stabilize it which is helpful when you are working with bias edges.
And finally, I buy more yardage than fat quarters, and have been known to buy a whole bolt of a fabric if I really fall in love with it. My usual minimum is two yards! LOL. And I am really waaay too lazy to wash and iron that much yardage. I'd spend all my free time washing and ironing. That's my story and I'm sticking to it!