You might be looking forward to going “oooh” and “aaah” over the stark minimalism of iOS 7, but you’ll be going “argh” if you try to install the new OS and everything goes horribly wrong.
Such disasters are rare, but that will be of little consolation if it happens to you. Before gleefully tapping the “GO! GO! GO!” button (or whatever Apple’s labelling it these days), you should therefore back-up your iOS data. Twice.
Set up iCloud
You get 5 GB of space on iCloud for free. Use it. Ensure you’re on Wi-Fi, open the Settings app and select iCloud. Turn on relevant options that aren’t already activated, to send important data (calendars, reminders, browser bookmarks, and so on) to the cloud.
Scroll down to and select Storage & Backup. Tap Back Up Now. One of two things will happen — either you’ll get a progress bar, telling you how long the back-up will take, or you’ll get a ‘Not Enough Storage’ warning. In the latter case, tap Manage Storage, select your device, and under Backup Options, deselect any items you can easily restore from elsewhere. (For example, if you back-up your photos to your PC or Mac, you can disable Camera Roll, often the biggest block of data.)
Your iCloud back-up will include app data, Camera Roll content, iTunes Store purchases, contacts and messages, notes and calendars, network and email account passwords, preferences, and Safari autofill data.
Back-up to iTunes
Yes, we know: iTunes is horrible. Tough — deal with it. Hold your nose, launch the app, select your device and click the Summary tab. (Depending on your existing setup, you may need to, like some kind of techie throwback, first plug your device in via its USB cable for your computer to see it.)
Under Backups, click Back Up Now. This will back up your iOS device’s data to your PC or Mac, and you can recover from this back-up in the event of a disaster. (If you use the iTunes sidebar, you can also right/Ctrl-click your device and select Back Up.)
Safeguard your photos
Photos are often records of precious memories (or precious drunken selfies) and losing them can be painful. Therefore, if you’re not using Photo Stream, start using it (activate it in the aforementioned iCloud section of Settings); this stores shots from your last 30 days, from which iOS devices will show the most recent 1,000. This does not count towards your iCloud storage limit.
Next, plug your device into your computer. If you’re using a Mac, use iPhoto, Image Capture or Aperture to make copies of your photos. If you're using a PC, select your device from the Portable Devices section, right-click, select "Import pictures and videos", and follow the wizard.
Do more things!
Post-install (or pre-install if you’re more organised), you’ll likely have to update a ton of apps so that they won’t blow up under iOS 7. Some won’t work at all and will never be updated, in which case it’s time to say cheerio and send them to oblivion (tap-hold until they all wiggle, and tap the close button to annihilate zombie apps).
Prior to doing so, you can always use the free iExplorer to access such an app (from Apps in the sidebar) and save its Documents and Library folders to your computer. These can then be sideloaded back later, if the app gets a surprise update. (This technique can also be used as an ultra-paranoid data-securing method pre-upgrade for ensuring your progress in a game will be very safe indeed.) Note also that iTunes doesn’t back-up music, and iCloud only holds content you’ve bought from Apple. iExplorer can be a quick way of getting music off of your device via ‘Media Library’, again in the sidebar. If you’ve local back-ups taken using iTunes, they will also be searchable.
You’ll also need to update iTunes (spit) to continue periodically backing up to your computer, which we assume you’re also backing up, right? (Stern look at camera. Theatrical about-turn. Exit into moody sunset, with ‘our work here is done’ vibe.)