About ⅛ c vinegar as a rinse/fabric softener in a front loader works for me. I wash on cold/cold, saves $ (unless someone is sick or for very young or elderly etc). If things stink or heavily soiled I add baking soda or borax then turn washer off while it’s in the washing mode and let things soak. I never rinse twice unless I accidentally add too much detergent. It’s believed to be worse to use too much detergent than too little. Manufacturers want you to use a lot. When I clean my coffee machine w vinegar I reuse the vinegar to help w baking soda to scour bathrooms and toilets.