Last week. I soak them as the first step of "doing my feet." I used to go to a nail salon but their price kept going up and I found I could do myself with a little effort.
It's been nearly a year since I last soaked them (although I may have to do it tonight as it feels like I'm walking on a bruise). I added epsom salts. However, I've since heard that epsom salts really don't do anything as the magnesium and such cannot be absorbed through the skin (as is supposed).