That fine line between 'stuff' and 'necessity' fluctuates. I could go a year without opening a certain cookbook, or wearing a certain dress (Scottish weather doth not allow for sundresses), but tossing them in the charity shop pile is not an option. Because I love them. Or something.
I calculated that I've saved nearly 25 metric tons by not having a car for 8 of the past 9 years (as I did have a car in Switzerland). I've not had the option of air conditioning or central heating. I'm easing into vegetarianism. So why is it so difficult to get rid of the stuff?