I am very dependent on my smartphone—what self-employed professional can make it without one these days—but I’m not eager to upgrade. With what I paid, I want it to last forever. As luck would have it, these surprising reuse tips might help me ensure just that!

1. Replacement iPod

The music players on most of today's smartphones are just as good as any iPod or MP3 player on the market today. So even if you upgrade to a new phone, you can keep your old device on hand for parties, traveling, and even soothing your newborn.

Cost savings: $40 – $300+ depending on the iPod or MP3 model and brand.

  • What you need: your old smartphone, headphones and/or speakers, music player (Spotify, Pandora, Google Play, and iTunes are all good), and—of course—tunes.
  • What to do: Load up the desired tunes and either sync via Bluetooth/Wi-Fi or plug in to an auxiliary speaker (or listen via headphones).

2. Emergency line

Currently the FCC (Federal Communications Commission) has a mandate that any smartphone, activated or deactivated, must still be usable for dialing 9-1-1. So if you live in an area prone to hurricanes or tornadoes (or even if you don't), keeping your old smartphone around and charged for emergency use only can be a smart plan.

Cost savings: Priceless!

  • What you need: your old smartphone, charger, designated "emergency only" storage spot.
  • What to do: Be sure everyone in your house knows where to find the emergency phone and also be sure to test it every so often to make sure it is fully powered and working.

3. Monitoring system

A surprising number of cool new apps allow users to sync together two smart devices to make an in-house monitoring system. This can be super-useful to monitor your baby, a sick child (or adult), an injured pet, and for other uses as well.

Cost savings: $40 – $300+ depending on the monitoring system you select.

  • What you need: your old smart device, a second compatible device, monitoring app (try Baby Monitor 3G for iOS and Android).
  • What to do: Place one device near you and the other in the room in need of monitoring. Power up your app of choice and go through the setup process (it takes just half a minute with Baby Monitor 3G). Monitor at will.

4. Gaming or educational toy

Whether you choose to adapt an old smartphone to teach your toddler or entertain your teen, chances are your old smart device already has the potential to double as a nifty portable edu-gaming toy.

Cost savings: $50 – $400+ depending on the console.

  • What you need: your old smart device, gaming and/or teaching apps.
  • What to do: Load the games or teaching tools you want onto your old smartphone and turn it over to the toddler or teen in question.

5. Housewide remote control

Depending on how much you want to spend and how fancy you want to get, you can turn your old smartphone into a simple one-device remote…or a house-wide remote system you can control from anywhere in the world (we chose the simple version here with free or low cost apps).

Cost savings: $25 – $400+ depending on the complexity of the system.

  • What you need: your old smart device, remote control app (iOS options, Android options).
  • What to do: Power up your device, fire up the app, and settle into the "control seat."

6. eReader

If you love to read but don't feel like springing for a fancy new eReader device, why not just use your old smartphone? This is an especially great option for when you travel since it frees up battery life on your main phone for other more essential uses (and the back-lit smartphone screen can be handy in low-light hotel rooms or airplane cabins).

Cost savings: $50 – $200+ depending on the eReader model and brand.

  • What you need: your old smart device, eReader app.
  • What to do: Load your books, fire up the app, and dig in!