So you broke down and bought a new gadget (or better yet, received one as a gift). Now you face a dilemma: What do you do with the old TV, cell phone, MP3 player, camera, or video game console you had before?

You have three basic options (not including "put it in the garage forever"): Sell it, donate it to charity/someone else, or throw it out. But how do you pick?

No matter which option you pick, don't delay. The best time to get rid of your old gadget or appliance is immediately after you get the new one. Don't sit on it for months (assuming you're sure the new device works): Gadgets and tech products lose value with near-exponential speed, so the longer you wait, the more worthless it gets. This is especially common when a large number of older-generation products hit the market at the same time, such as right after a new upgrade is released.

With any old gadget -- and especially considering today's economy -- the first step should be obvious: See what it's worth. Head to eBay and do a "completed items" search and check the selling prices for comparable-condition products. Be warned: Prices are always all over the map (and make sure you're looking at actual sales, not listings with high initial prices that didn't get any bids), but you can get a good idea of what a reasonable price for your item is this way. Remember that the product's condition is important, as are extras (cases, manuals, original packaging) which will help you get more.

Set a floor for what you're willing to sell it for. Generally this should be the value you place on the time and trouble it takes to list the product for sale online (plus fees) and ship the product, plus the value you would expect it to have as a donation or hand-me-down gift. If the going price is less than this value, don't bother selling it.

If you decide the product is worth something, try selling it -- if not eBay, then in a fixed-price setting like Craigslist. In general, you'll get a better price on eBay, but many items won't sell there at all: If you have an enormous TV that would cost $100 to ship, you'll do better selling it locally where someone can pick it up.

If you decide not to sell (or if you get no buyers), get creative with your gear. Your old Xbox or PlayStation 1 may be useless to you, but a younger kid may enjoy it as a first gaming console.

If you can't sell or give away an item, unless it is totally non-functional, donate it. Many charities will take technology products and use them for training workers or sell them in resale shops. Even if a charity ultimately gets only a dollar for the product, that's still better than it ending up in a landfill. And of course, there's a tax write-off for you in there, too.

Remember that most gadgets can and should be recycled, not thrown in the trash. In many areas it's illegal to throw tech products away as general refuse. Check with your municipality before putting anything with a circuit board in the trash.