Contrary to the name, softeners do not soften the fabric but water and add more ionic detergent plus some smell. You get a bit more efficient washing as long as

Contrary to the name, softeners do not soften the fabric but water and add more ionic detergent plus some smell. You get a bit more efficient washing as long as you reduce amount of washing medium. Oh, and they do impart negative charge to the fabrics making them seem fluffier. Some softeners do have protective oil or silicone or polysorbate that will coat the fabric protecting it more. (Similar mechanism to hair rinse.) This actually will protect the fabric from some wear. These chemicals cannot really be added to washing detergent as it would counter its action. Certain silly people say the thin coat will interfere with future washing. I recommend testing instead of silly assumptions. (The layer is nonstick and waterproof which means your clothes will get less dirty and it is easier to remove anything on them... So you can use less detergent, time, force and water later. C.f. impregnated vs nonimpregnated wool.)