After following my own advice, my data usage fell to 100 MB today. That's a big improvement, but still higher than it should be.

My usage would have been down to 20 MB if not for two things:

  1. A sudden 40 MB burst on my way to work, which disproved the Podcasts app theory.
  2. Downcast deciding to download a 40 MB podcast when it couldn't find the local file, despite being set to only use Wi-Fi.

With what I've learned today, I'm hoping to finally get my data usage back to normal.

That being said, I'd like to address some feedback from my original post and share what I've learned today.

My Headline

Some of my readers have criticized the title "The iPhone 5 is a Data Pig," as most of the issues I pointed out are not iPhone 5, nor even iOS 6 specific.

I stand by that title. First, I'm speaking from my own experience. I never updated my iPhone 4 to iOS 6, nor did I own a 4S, so I cannot personally speak for those configurations. My excessive data consumption began when I switched to the iPhone 5, with little change in my typical use pattern.

Second, I knew my original post was only the beginning of the story. I'm still not convinced that the new hardware isn't a factor in the excessive data consumption. Also, I think LTE plays a big role. I had used iTunes Match over 3G many times, with data usage nowhere close to what Match uses on the iPhone 5.

DataMan Accuracy

Some of my readers have questioned DataMan's reporting. However, the 150 MB it logged yesterday matches up with Verizon's tally. For me at least, it's far more accurate than Apple's built-in measurements.

Podcasts

Yesterday, I suspected that Apple's Podcasts app was causing data usage, even when set to only use Wi-Fi. Specifically, I believed that it was causing a slow, steady uptick in usage throughout the day, along with sudden bursts of 40-50 MB.

I now think that I was wrong. Even after deleting the app, I experienced a sudden and mysterious 40 MB surge in usage this morning. I was completely lost until a reader clued me in to a Safari bug.

Safari Bookmark Sync

Michael Fessler pointed me to widely reported bug in Safari's bookmark syncing feature. I turned this feature off (Settings -> iCloud -> Safari) and have noticed no mysterious data use since.

More permanent fixes appear to involve either:

  1. Backing up to iTunes, editing a configuration file, then restoring from the edited backup.
  2. Turning off Safari bookmark syncing on all connected iCloud devices, then wiping the iPhone and starting from scratch. This is the option I've chosen.

Downcast

Back to podcasts. Yesterday, I recommended my old favorite, Downcast, as a replacement for Apple's official Podcasts app. I hate to say it, because I love the app and its developers, but this was bad advice.

I tried to play a previously downloaded episode of Hypercritical. However, the file apparently didn't transfer to my new phone, so Downcast, despite being set to only use Wi-Fi, opted to stream the episode. Before I could act, it had cached the entire 40 MB episode over my Verizon LTE connection. According to the developer, there is currently no option to change this behavior.

To make things worse, my battery had dropped to 26% by noon, where it had been closer to 50% the past 2 days. I have no doubt that Downcast is the cause. The developer suggested that Downcast's iCloud sync feature (surprise!) caused the battery drain. However, it's completely academic, as I can't afford to use an app that gulps down so much data so fast.

So goodbye Downcast, and welcome back Podcasts. Despite its flaws, it's power efficient and uses special Apple juju to download new episodes without my intervention. It gets at least another day to prove itself.

What's Next

I've decided to restore my iPhone 5 and start fresh. It's probably what I should have done from the start. It'll eliminate all the old cruft, and maybe even fix a few other miscellaneous issues. Most of my iPhone's data is synced to some kind of cloud, so this process isn't too painful.

I'm going to start with only the preinstalled apps, optional apps created by Apple (Podcasts), apps officially endorsed by Apple (Twitter, Facebook, Yelp), and DataMan. If data consumption improves, I'll start adding third-party apps back. If it stays the same or gets worse, I'll remove apps and turn off features until I identify the source.

I am determined to get to the root of this. This story is far from over. Watch this space.