A huge contributor to clutter is simply not knowing how long to keep things. Think about all of those travel toiletries you've accumulated, or the pile of magazines you haven't read, and quite frankly, aren't sure you'll get to. It's important to set a time limit on everything--from clothes and shoes to mail and paper work--so that it doesn't become clutter.
I love paper, but I've learned the hard way that I can't indefinitely hold onto every piece of paper that crosses my threshold. Ditto for makeup, shoes and handbags. At some point, it's time to let them go, so working with some experts, I created a guide to how long to keep everything. Use this as a reference when you're decluttering and making decisions on what to toss, recycle, or keep, or what to save and store.