Tips for reducing data usage
The four Macs, six iOS devices, Apple TV, VoIP telephone adapter, and numerous other Net-connected devices in the house presented a challenge. Unplugging the cable modem would have worked, but at considerable inconvenience. Instead, I decided to take multiple less-draconian measures:
Turn off automatic updates. So far this month, I've downloaded more than 14GB of updates for Apple software alone on a single Mac. Having that happen behind your back when you're running low on data isn't wise. On a Mac, go to System Preferences > App Store (Yosemite) or Software Update (earlier versions) and uncheck everything under Automatically Check for Updates, plus Automatically Download Apps Purchased on Other Macs. On an iOS device, go to Settings > iTunes & App Store and turn off Updates. (While you're at it, you might want to turn off iTunes Match and automatic downloads for Music, Apps, and Books.) You'll still be notified when updates are available, and can download them manually as needed.
Use iTunes for iOS backups. I had already backed up my iOS devices to iCloud, but during my data-constrained weeks I had to restore two devices. That meant downloading many gigabytes of data from Apple's servers. Had I backed up locally to iTunes, I wouldn't have faced that problem. To configure an iOS device for iTunes sync, plug it into your Mac with a USB cable, select the device in iTunes, select Summary, and then select This Computer under Automatically Back Up.
Turn off My Photo Stream. Whenever you snap a photo with your iOS device, My Photo Stream copies it to iCloud and then down to your other devices. Consider turning it off temporarily. On a Mac, go to System Preferences > iCloud, click Options next to Photos, and uncheck My Photo Stream. On an iOS device, go to Settings > iCloud > Photos and turn off Upload to My Photo Stream. (In iOS 8.1, also turn off iCloud Photo Library.)
Stop streaming. Painful as it may be, stop using your Apple TV — or use it only to play video stored on a local Mac or iOS device. Streaming audio and video from sources like iTunes and Netflix consumes loads of data.
Choose voice over video. Video calls using Skype, FaceTime, Google+ Hangouts, and similar services use a lot more data than voice calls or text messages.
Watch online backups. When you're data-constrained, consider excluding large files such as virtual machines, movies, and big disk images from cloud backups. Back those up to a local hard drive instead.
Borrow bandwidth. I took my MacBook Pro to coffee shops and the library, using their free Wi-Fi to download software updates, back up files, and do other bandwidth-intensive tasks — and turned off those services while at home. Had I asked, one of our neighbors might also have lent us a cup of Wi-Fi.
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