I'm well aware that many claims that those
laundry balls don't work, but I have an impression that they work for me. My grandmother bought two and gave me one-- I've never been disappointed with it. If my laundry is clean and soft, why should I not use it? When I use washing powder with no fabric softener, my clothes are damn thick-- but not when I use just that laundry ball.
My usual laundry set ^^ A laundry ball + tea tree oil. I use the latter when I wash towels or underwear-- because of its antibacterial properties.
I will have to check if my laundry is the same with no detergent and no laundry ball. The laundry ball certainly was helpful when I washed&dried my down feather jacket.