So save its battery and use your old device for these menial tasks.
Add in a cheap SD card for storage, which will also take the load off your main device, and enjoy it as a dedicated audio/video media player.
8. Portable games console
Gaming is big business on tablets and phones.
So not only is your Android device a solid gaming platform – though if it's an older device newer games may not run – but what it can also be is a classic gaming platform through emulation.
9. A remote IP webcam
IP Webcam is a neat free app that turns your Android device into a handy IP-based webcam, so you can connect to it from another Android device or any network computer using a browser, or even Skype.
It supports audio and a host of clever features such as streaming to VLC.
If you're after a cheap Wi-Fi IP camera, this certainly does the trick.
10. Video camera
It's unlikely you're going to want to use an old Android device as a spare camera, as we'd imagine the camera quality leaves something to be desired.
But that's not to say it can't be used as a decent video camera, though.
The moving image, being lower resolution, is a lot more forgiving on poor quality sensors and lenses, while even old devices can offer HD 720p encoding.
Again, slap in a suitable SD card and you have a device to capture hours of video.
11. Sat nav
Grab Navfree. It is, importantly, an offline sat-nav app, as otherwise with Google Navigation you'll need a data connection.
Make sure you grab the UK maps and postcode downloads and you're ready for a bit of free navigation.
Using a spare device means you could more permanently fix it within the car with attached power without worrying about it.
It'll also work without hassle when your main phone might not have any signal.