Which Gadgets Can Your Smartphone Replace?

Whether you're buying a new smartphone, or shopping for more gadgets after getting one, you might be thinking: "Do I still need a (BLANK)?"

It's a valid question. Smartphones are do-it-all devices, and a single app for the iPhone (or an Android smartphone) can replace a device or a PC or Mac software package, even ones costing hundreds of dollars. That means less to carry around and fewer new gadgets to buy, and it might even mean you can sell or recycle some of your old devices.

The question is, which ones? How do you tell?

Calculators

This is an easy one, right? Not so fast. If you need a graphing calculator for a school class, you're probably going to want one with hardware keys, especially when today's scientific calculators have advanced features and tie into the educator's software.

As we'll see, this is the trend for everything else. If you need only basic functionality from something, an all-in-one smartphone may be all you need.

Digital cameras

Here's a case where smartphones are pushing things out of the market. As smartphone cameras get more advanced, using hardware flashes and even built-in photo editing software, they're making point-and-shoot cameras basically obsolete. You can even buy tripods and zoom lens add-ons for some smartphones.

On the other hand, if you're a professional photographer or serious photophile, you're going to want a more powerful DSLR camera (or three) with features like replaceable telescopic lenses. Maybe not to carry with you everywhere, but definitely to take to events.

Music players

Between streaming Internet radio apps, and stores like iTunes and Google's, there's not a whole lot of reason to buy a separate music player if you have a smartphone. Even audiophiles might appreciate the HTC Rezound, an Android smartphone that uses Beats Audio.

On the other hand, an Apple fan who loves her iPod Nano ($124) might find Google's music app to be cumbersome, and to not work with her iTunes collection. That's one reason to keep an old gadget around.

E-readers

Color e-readers like the Nook Tablet ($249) can read some things that aren't in the Nook Android app, like animated children's books. They also have larger screens than smartphones. Meanwhile, black-and-white e-readers have batteries that last for weeks, and are easier to read books on, especially in daylight.

E-reader phone apps will save your place while you're reading though, and let you get back to that place on your separate e-reader device. So if there's not enough room for your Nook in your handbag, a smartphone might save the day.

Game consoles

A lot of people who buy a portable game console do so because they want to play a specific game that they need it for. Pokemon, for instance, isn't on any smartphone.

If you've got enough games on your smartphone to keep you happy though, you probably don't need to buy a separate console. And if your old one is collecting dust, it might be time to consider a trade-in.

Note: This was written by a Yahoo! contributor. Join the Yahoo! Contributor Network to start publishing your own shopping guides.