Possessions that you use regularly, value, and are worth more than the trouble they bring you might make life simpler. Possessions that are merely things you're storing "in case you need them", and are moving from one place to another, certainly don't make your life simpler.
I've known many people (including myself) who have found themselves in a position where they wanted or had to move and discovered in the process that when it came down to it, they could happily live without half of the stuff they had accumulated over the years. I did that in my most recent move, and a year later I do not miss any of it, and am still getting rid of things (30+ computer science books recently, and am now moving onto the photography equipment that just gather dust in the closet).