Never. Like my mother before me, I don't own an iron, and I avoid buying clothes that wrinkle easily (linen!) and have to be ironed. On the rare occasions something needs ironing, like my daughter's fancy dress, my MIL volunteers to do it at her place in exchange for watching my daughter try stuff on and getting input into dress options. Win-win.
My mother actually did buy an iron when I was about 10 -- to use purely for those 1990s bead art projects that required ironing or baking. She didn't want to turn on the oven in the summer.
