The problem for me is every year when i try to sell my older devices, i find it difficult to get what they are worth. I face scams on all the major marketplaces, and most online choices right now wont give me the value. On the other side, customers are buying devices that aren't certified, full of fake parts or they are just plainly getting scammed. See the iPhone soapgate. Not only is this a huge problem, it's fragmented and inconvenient. there should be one app where you can buy sell, certify and swap your device and get paid the same day. This will add more trust, make people think refurbished or pre owned more and help create a more sustainable way to consume and access technology.