"Three moves are worth one fire."
If you're a pack-rat, don't wait for a fire to whittle your possessions down to a manageable level. Moving offers a better (if less efficient) opportunity to unstuff your garage, attic, basement, closets, cupboards and other areas of your home. After all, it's easier and less expensive to move with less stuff.
As you begin to plan your move, search every room in your home for unneeded and unwanted items. If you haven't used something in a year, chances are you'll never miss it. Separate the cast-offs into different groups--items to donate, items to sell and trash. Then be sure to follow through on your decisions swiftly, before you have a chance to change your mind.