Now playing: Watch this: 8 ways to repurpose your old phone

It's hard to believe, but smartphones as we know them have been around for nearly a decade. And chances are good you've upgraded at least once during that time, if not many times.

Usually, that upgrade leaves you with your old phone and a question: What should I do with it? Most common answer: Sell it. That's a good way to help defray the cost of the upgrade.

However, that's not the only option, and not necessarily even the best. Instead, consider repurposing that old phone. You might be surprised at some of the feats it can perform. Here are some of my favorite uses for a discarded Android:

1. Keep it as a backup phone

Enlarge Image Samsung

It's a hard truth: Phones get lost, stolen and broken every day. I don't know about you, but I'd be in pretty dire straits if something happened to my phone.

The straits would be less dire, though, if I could just grab my old standby. I'd still have access to my calendar, contacts, email and the like (because they're all synced), along with daily-use apps like Facebook, Spotify, Twitter, my password manager and so on. There's really no better short-term rescue option.

In fact, if you still have your new phone (assuming it's merely busted and not lost or stolen), you can probably just pop the SIM card out and back into the old phone, restoring voice and data until repairs are made.

Of course, you don't have to stick the old phone in a drawer and leave it there in case of disaster; you can also keep it as a low- or even no-cost second line. For example, if it's an unlocked GSM model, grab a SIM card from Freedompop (about $13, or AU$17, £10) and sign up for the Basic plan. It affords you 200 voice minutes, 500 text messages and 200MB of 4G data per month -- at no charge.

For more on this idea, check out my post on how to set up a backup phone.

2. Use it as a dedicated camcorder

Whatever you're recording -- a wedding, a kid's soccer game, a music video or your sure-to-win-the-film-fest indie movie -- nothing beats multiple cameras. When it comes time to edit, you can mix footage from different angles and positions to create much more interesting video.

Needless to say, your old Android can make a great second camera. Even older, lower-end phones can usually capture at least 1,920x1,080-pixel video at 30 frames per second. Clear out as much storage as possible to make room for new footage and you're good to go.

3. Use it as a baby monitor

Enlarge Image Sleekbit

Speaking of video, an Android phone with nothing else to do can easily pull baby monitor duty, and in fact can rival or even exceed standalone products costing a pretty penny.

All you need is an app like Dormi, which is designed expressly for this purpose. In addition to both audio and video monitoring, the app offers two-way audio so you can talk to (and hopefully soothe) a crying baby from afar.

Speaking of afar, you can tap into the audio/video feeds from just about anywhere, provided the Android phone is connected via Wi-Fi. Dormi also supports multiple "parent" devices to the phone that's doing the monitoring. The app is free but limits you to 4 hours per month of monitoring. To unlock lifetime monitoring, there's a one-time fee of $9 (AU$11.89, £7).

4. Use it as a video doorbell

No baby? Consider putting your Android on door duty instead. No, the phone itself doesn't go outside; you'll need to install either an outdoor Wi-Fi webcam or a smart doorbell. Then your phone can serve as a full-time video monitor, one that lives on, say, a coffee table or nightstand.

For example, the Canary Flex is a versatile, security-minded webcam that can go just about anywhere -- including outside. Alternately, check out video doorbells like the August Doorbell Cam, DoorBird Video Door Station, Ring Video Doorbell and SkyBell Video Doorbell.

5. Give it the GoPro treatment

Enlarge Image Velocity Clip

One final video option: Turn your old phone into a GoPro. Again, that's a solid camera in there, so all you need is a way to mount it for action-video duty. Velocity Clip, for example, offers phone mounts for your bike, chest and head, all of them priced in the $40-to-$50 range (AU$53-AU$66, £31-£39) . Granted, a smartphone is a little unwieldy when strapped to your head, but it's still way cheaper than buying a separate GoPro.

Whatever mount option you end up with, hit up eBay for a cheap Bluetooth camera-shutter button. (They're available for as little as a few dollars.) That way you can start and stop video recording without having to fiddle with the phone while it's mounted.

6. Create a dedicated VR headset

Enlarge Image Battop

Get ready for a surprise. That old Android phone of yours? Virtual-reality powerhouse! It's true: A smartphone can serve up some terrific VR experiences. All you need is a headset and some apps.

Even more surprising: a headset won't cost you much. Amazon, for example, offers dozens of universally compatible VR goggles priced in the $20-to-$35 range (AU$26-AU$46, £15-£27). Look for a model that lets you adjust focal width and length, the better to accommodate less-than-perfect vision. I also recommend choosing one that comes with a Bluetooth gamepad, the better to control games and access menus.

As for the apps, hit the Google Play Store and search for "VR" or "Google Cardboard." Both will reveal a wealth of games and other experiences that are compatible with nearly any Android and VR headset.

7. DIY Google Home

Don't want to spend $129 for Google's voice-powered smart speaker? That's understandable, especially when you can put together something similar for a lot less. Unless it's really old, your old phone can listen for and respond to voice commands, same as a Google Home. So all you need is a speaker to round out the equation.

What kind of speaker? And what kinds of things can you do with a phone-brain that you can't do with an actual Home? Find out in "Turn a spare Android phone into a Google Home."

8. Leave it on your nightstand

Gerard Puig

An old phone might just be the best thing to hit your nightstand since the lamp. Because in that one spot, it can serve countless purposes:

Alarm clock: Not ready to roll out of bed yet, but don't want to fumble for your phone to turn off the alarm? Check out Voice Snooze Alarm, which is exactly what it sounds like: An alarm clock you can snooze with a customizable vocal command. (Come on, you know you've always wanted to tell your alarm to "Shut the **** up!" Now you can.)

Clock radio: TuneIn Radio is a good choice, as it has both alarm and sleep-timer features.

Dedicated e-reader: iBooks, Kindle, Nook, OverDrive -- you don't have to limit yourself to just a single app.

Meditation player: I'm partial to Calm, but there are a zillion others.

Spare Roku remote: Check out the latest update.

White-noise machine: I don't have a particular favorite; hit up the app store for lots of choices.

Any other suggestions for an Android phone by the bedside? Or anywhere else, for that matter? Let's hear your ideas for reusing your leftover handset.

Editors' note: This article was originally published on April 18, 2017, and has since been updated.