1. You have twice as many as you need. Take inventory of your duplicate items. If you own enough spatulas and coffee mugs to supply a small diner, it's time to shed a few.
2. It's a gift you don't love. "Sometimes when we give away a present, we feel like we're giving away the person," says Elsa Jewett, a feng shui consultant based in Denver. Remind yourself it's just an object.
3. It's not worth repairing. Search for similar items on eBay; if your item's current value is less than the cost of repairing it (hello, broken printer from 2004), then toss and replace. Otherwise, give yourself a deadline. If you don't get around to fixing the thing within six months, you can probably let it go.
4. Your gut says lose it. Don't second-guess your instincts. "A lot of people worry they'll have regrets," says life coach Gail Blanke, author of Throw Out Fifty Things. "They're afraid that one day they'll need that exact thing. But 99 percent of the time you just don't."
5. You don't know what it is. UPOs (unidentified plastic objects) get 30 days. If they're still a mystery one month later, dump 'em.
Keep it if...
1. It's sentimental gold. "The more memorabilia you have, the less emotionally valuable each individual item becomes," says Emily Wilska, an organization consultant in San Francisco. Instead of saving every card your beloved uncle ever sent, pick the one that captures his spirit best.
2. It fits your life today. Your possessions should support who you are right now, not the person you were five years—or five pounds—ago. Your ten-year-old LBD that still looks great? It stays.
3. You think it's gorgeous (even if no one else does). Stuff that makes you smile—like the glittery clothespin reindeer your child made in third grade—doesn't count as "clutter."
4. You'd buy it again. It's tough to be objective about your own belongings. So ask yourself, What would I do if I saw this in a store?
5. You'll find a place for it. "Putting it back in a box is just predisposal," says Erin R. Doland, author of Unclutter Your Life in One Week!! Any item worth keeping is worth creating a space for.
Next: Where to donate all the things you've just gotten rid of (really, don't just throw them away!)