my battle with clutter

I have some interests which require a lot of space in my home. Trying to organize and keep track of the various things I have seems to take a whole bunch of time. I'm thinking of installing closet organizers in some of the spare rooms so that I can regain some of the empty space I loved so much when Sharry and I first got our home. Plus, Charlie won't eat what he can't get to.

Other than closet organizers to provide more useful storage, I can't seem to think of a practical solution to clutter. I'm not a guy who puts stuff away unless I'm really done with it. I can (and do) read 12 books simultaneously, and re-read books I like many times. We have momentos and stuff from college that doesn't seem like it will ever really be touched. What is a person to do?