Posted with permission from Popular Science

Everything you need to do before selling or recycling your devices

Smartphone
Don't ditch your old phone until you've followed these steps.

If you're getting rid of your old laptop, smartphone, tablet or other gadget—we've previously covered some of the best recycling options—there are steps you need to take before parting with your unwanted hardware to protect your private data.

Are all your photos stored somewhere safe? Are you sure your laptop's new owner can't get at your banking spreadsheets? Disposing of old hardware can be a privacy minefield, but staying safe isn't difficult if you know what you're doing.

Back up all your important data

iCloud
Apple
iCloud is one way of getting your files spread across several devices, but you'll have to pay for the privilege.

Firstly and perhaps most obviously, you need to get your files off your old devices and on to somewhere new—preferably in two new separate places (like another computer and the web) to make sure if one backup fails you've got another in place.

If you're already using apps and services that are based on the web, like Gmail or Netflix, then you can relax a little—all your content will be waiting for you on the new device the next time you sign in.

For those not using web-based services, there are several ways to save your data. Programs like Dropbox, Google Drive, CrashPlan and Backblaze will all put your files in the cloud for you, but plans large enough to duplicate your entire computer will cost anywhere from $50-$100 annually (the most expensive plan, Google's $30 TB/month, costs $3600 annually). Or, you can invest in an external hard drive and simply copy your files over from your device—though it may be worth getting a second hard drive as a fail-safe in case one gets corrupted.

Windows and macOS have their own built-in solutions in the form of OneDrive and iCloud, respectively, that both work on mobile (as do Dropbox and Google Drive).

OneDrive
David Nield/Popular Science
On Windows, OneDrive is the built-in backup solution, but again you don't get much space for free.

Both Android and iOS back up certain bits of information automatically—see here and here, respectively, for details—but they don't necessarily get everything, so verify your files are safely in place before starting your eBay auction or heading to the local recycling depot.

And while you're transferring the contents of your smartphone, Google Photos is an excellent cross-platform service that's free to use, though it will compress your photos to 16 megapixels and your videos to 1080p. However, there are plans you can pay for to keep your memories in full resolution.

Unregister apps and software

Unregister devices
David Nield/Popular Science
Some applications, like Photoshop, can only be installed on a certain number of computers.

A lot of applications out there—Microsoft Office, iTunes, Photoshop, Spotify—keep a record of how many devices you're logged onto at the same time. If you try to register a brand new computer without unregistering the old one first, you might get a nasty surprise.

To be fair to the likes of Microsoft and Adobe, they make it fairly easy to manage your active devices, but the best approach is to make sure you completely sign out of old phones, tablets, and computers.

In the case of iTunes, for example, you need to open the Account menu and select Authorizations then De-authorize This Computer. You should also sign out of your Apple ID as well from the same menu. What's more, Apple suggests signing out of your Apple ID account and disconnecting iCloud if you're getting rid of an iPhone or iPad—there are detailed instructions for how to do this on Apple's support site.

iTunes
David Nield/Popular Science
You also need to make sure your two-step logins will work without your old device handy.

Over on Android, you don't have to sign out of your Google accounts before wiping your phone (see below), but do make sure all your stuff is backed up. You might need to deauthorize certain apps though—Google Play Music is one example where you have a limited number of devices you can sync to. As a general rule of thumb, the services you're paying for are the ones you need to look out for.

If rely on your phone for getting past two-step authorization protection on sites like Facebook and Twitter, you might need to temporarily disable this feature and set up on a new device before you get rid of your old one. Check the small print for the services you're using (here's how to move Google Authenticator to a new device, for example).

On mobile devices, you can simply download your apps again on a new device (Apple and Google will remember which ones you've paid for). However, on both Windows and macOS desktop computers it's not quite as straightforward. Always double-check you can get your software back, which usually means re-downloading it from the web. Games are another set of programs you should check—here's the process for moving a Steam library from one computer to another.

Securely wipe your old devices

Windows 10
David Nield/Popular Science
Windows 10 has a reset feature that's fairly simple to follow.

With all your data safely stored elsewhere, and all your apps and services safely deauthorized where necessary, the last step is to completely wipe your devices and remove all trace of your activities so your files can't be recovered.

On phones and tablets, this is pretty straightforward. On iOS, open up the Settings app then head to General, Reset, Erase All Content and Settings. This will wipe your iPhone or iPad and return it to the state it was in when you first got it (the opening setup screen for iOS, in other words).

On stock Android, the option you want is in the Settings app: choose Backup & reset then Factory data reset to start the process. If you're not using the pure version of Android straight from Google then the menu labels might not be exactly the same, but there should be a similar option somewhere in the settings.

Erasing an iOS device
David Nield/Popular Science
With everything off your iOS device, you can safely wipe it.

On laptop and desktop computers the reset process is a bit more involved.

In Windows 10, open the Settings panel from the Start menu then choose Update & security, then Recovery, then click Get started under the Reset this PC heading.

For the latest versions of macOS, reboot your machine, hold down the Command+R keys and choose Disk Utility from the menu that appears. Choose the main disk drive, click Erase, and select Mac OS Extended from the Format menu. Quit the Disk Utility program, choose to reinstall macOS, and you should be back with a clean version of your operating system.

In the case of Windows and macOS you can just delete files and apps without reinstalling the operating system, but it makes it easier for the computer's next owner to get them back, especially if you're using an older mechanical hard drive rather than a modern SSD. For the last few years Macs have been moving towards SSDs, so you should be safe, but on Windows enlist the help of a free tool like Eraser or Blank and Secure to make sure your data really is gone forever.