I cannot imagine washing fabric in the bath tub. Of course, I have a bad back, so it would be impossible for me. Even before the back issues, I serge the cut ends of the fabric (for yardage) and wash it in warm to hot water, a little soap (not much) and dry it in the dryer. I iron all of the fabric at one time. I've had problems with several pieces of fairly expensive fabric, but especially the reds. The first time I encountered the "bleeding" problem was in 2010. I was making a whole-cloth embroidered quilt with red borders. The red fabric bled rivers, even after I washed it. I've tried all of the home remedies, vinegar, epsom salts, etc., and none of that worked. The reason for that is that the dyes used today by fabric manufacturers is NOT organic, it's totally chemical; therefore, the organic remedies just don't work. Also, another reason for pre-washing everything is shrinkage. Cotton fabric will shrink. Obviously the more expensive fabrics should shrink less, but if fabric is going to bleed or shrink, I'd prefer that those things be brought to light BEFORE I start cutting out a quilt. Also, discretion is the better part of valor, so when I wash a quilt, or a recipient of one of my quilts does so, I use and advise my quilt recipients to use Color Catchers. If I have a fabric that bleeds, I treat it with a laundry treatment which is a dye fixative which almost always works. Even after the fabric has been treated, I test it to make sure it no longer bleeds. If it does, I don't use it. I cannot afford to have a quilt be ruined by a bleeding fabric. We all put too much time planning, and expense in making a quilt to have that quilt ruined by a bleeding fabric. I know that treating a fabric that bleeds is a lot of work, but I'd rather spend that time and effort on treating the fabric, than spend it making something that might be ruined in this manner. I wash everything because I want the shrinkage issue resolved before rather than after I've done all that work. JMHO!