For special clothes that you want to last longer, hand wash them in hair conditioner. As hair is a natural fibre, so is wool, silk and cotton. Most of your good clothes are not worn so much as they are literally dirty they just need to be soaked in conditioner and rinsed.
I apply this to my own cottons, silk or woolen fabrics that require "Dry Clean Only" and it has never failed me. This method will add life to your fabrics rather like your hair.