I returned from living overseas for many years, started teaching elementary school and became a pack rat! Ten years later, my garage is filled with textbooks and storybooks.
I love my home and have decorations for every season, as well as paint and supplies for unfinished projects. My fiancé is a computer technician and has several shelves loaded with books, as well as tools. I would like to use my two-car garage for two cars! Help me!
It's all about limits. Think about when you're teaching kids and they have to keep different subjects in different notebooks, or they have to keep a reasonable amount of stuff in their lockers—it's no different with your garage.
You need to establish a clear limit on what you're okay with keeping. Two shelves for textbooks, three bins for holiday decorations, an album and memento box for each of your overseas trips. Then you need to consistently work through the items in the garage for a half hour every day, working toward cutting items down to the limits you set.
Doing nothing is the worst thing you can do. Set some limits and understand that small steps, consistently applied, will yield results.