I've kept all my old phones. I just can't bear to part with them, knowing they might have personal information that somebody could hack if they tried really hard. You never know. I use them as alarm clocks and just to note the time. Otherwise, they sit in a drawer. When I die, my family can worry about what to do with them!
Selling a relatively new but old device is always a great option for cash. If you've got a device that isn't worth much, then you can turn it into a daily planner by mounting it on a wall with the right apps. The same goes for alarm clocks, wall clocks, thermometers, and they can even be used in a home automation system. You can repurpose an old phone into just about anything.
I kept my old phone as a backup, but honestly, I don't see me needing it any time soon. I used the old phone for a number of years, and my current phone is also a few years old, so far. I don't really see the need for constantly upgrading my phones, because I don't really have any need for newer and thinner phones, most of the time. My old phone also isn't worth enough for me to go about the trouble of selling it, due to its age and wear.
Last year I replaced 5 different phones with the latest and greatest. I sold each one of them on Craigslist or Ebay for over $300 each. I turn around and use that money towards the next big thing so am able to afford my crazy phone habit.
I still have my old phone though it's not working properly anymore, and with that reason alone, I haven't thought of selling it, I just don't think any sane person would be interested in buying a broken phone, right? Besides, that old phone contains too much memories, I'd like to keep it with me as long as I live.
I always trade in my old phones. I used to keep them, I had about 4 or 5 at one point but they were just stuck in a draw collecting dust so I had a look online, found a few websites that bought phones and other electronic devices, and sent them off.
We keep a few backup phones around. With phones we're definitely getting rid of, I check the trade in price at amazon and the other sites. Then I try to sell it on craigslist for more than that. Sometimes that gets me more money but sometimes it doesn't work out. I usually don't try to sell it on my own for more than a week or two. After that, I send it in to wherever had the best price and terms.
