I rinse my fabrics in the sink so I can see if they are fading. Then I dry them in the dryer to take care of any shrinkage.
I don't do this if it's for a wall hanging that won't be washed.
I had one navy blue print that was terrible and never stopped bleeding. I won't use if for anything. I also had a black cotton fabric from JoAnn's Fabrics that faded and faded--the water turned black over and over. I had used the same fabric from a different bolt that didn't do this, so I suspect there was a problem in the factory process.