I just got off the phone from speaking with an AT& T customer service representative. We talked for almost 45 minutes about my current data plans on my iPhone 4 and my iPad. Currently, I have an unlimited plan on my iPad. When I first got my iPad, I exhausted the $15/month 250MB data plan in just one weekend. Ever since that time, I've maintained the $30/month unlimited data plan. I was concerned because I use my iPad more often and differently than I use my iPhone. I use my iPad mostly for reading news (RSS feeds and dedicated apps like the BBC ) and work — email and calendar. Occasionally, I'll watch a Netflix movie while sitting in bed. However, my iPhone is used mostly for communication, although not necessarily voice. I use several social media apps — Twitter, Foursquare, Instagram — and quite several photographies, choosing to instantly upload and share my images. I very much expected that my iPad data usage would be higher than my iPhone 4 data usage. It appears that it might be the other way around.
Just before the iPhone 4 was released AT& T changed the nature of their cellular data plans. The Unlimited plans were unavailable for new customers — existing customers got to keep it — but AT& T now offered a $15/month 250MB plan and a $25/month 2GB plan. When we got out iPhones, I signed my wife up for the 250MB plan, and I got the 2GB plan. I assumed that between Twitter, Foursquare check-ins, and photo uploads — I have several camera apps — that I would need the bigger plan. Analyzing our current usage over the last 9 months, it appears I was correct. My wife averages about 100MB/month, and I average about 500 MB/month. AT& T's provides excellent tools for analyzing iPhone data and voice usage. I am closer to maximizing my iPhone data plan than my wife, but neither one of us is going over.
AT& T does not provide a tool for analyzing the iPad data usage. Perhaps that's on purpose or maybe just an oversight. In any case, I downloaded an app called My Data Usage Pro to analyze my iPad data use over time. I've been only using the app for a few weeks, so the data is not conclusive, but I believe that I am not fully utilizing the Unlimited plan as I assumed I would. Most of my data usage appears to be over Wi-Fi. I have Wi-Fi at work, at home, at cafés, around the Princeton University campus or via Comcast/Xfinity hotspots around town. In fact, from my desk at the office, I can pick up the Xfinity hotspot quite clearly. So far this month, I've used just over 500MB of Wi-Fi and less than 5MB via cellular 3G.
When Apple introduced the Verizon iPhone earlier this year, they also released an updated OS — for Verizon only at first then later for AT& T. iOS 4.3 added, among other things a Personal Hotspot feature. This feature enables the iPhone 4 to share the cellular data connection with your Mac, PC, iPad, or other Wi-Fi-capable devices. With this, the Personal Hotspot feature enabled, I would be able to share my cellular data connection with up to five devices at once. Three of those connections would be via Wi-Fi, the remainder are split between Bluetooth and USB.
After talking with the AT& T representative I've decided to drop the cellular data plan on my iPad and enable the Personal Hotspot feature on my iPhone 4. The plan cost $45/month and comes with an additional 2GB of data per month for a total of 4GB. The hotspot feature is not available with unlimited data plans. If you enable the Personal Hotspot feature, you'll have to give up your unlimited data plan on your iPhone. Based on my analysis of my data usage, I most likely won't notice. In any case, AT& T will warn me if I am about to go over my plan limit and I can purchase an additional 2GB for $25. Assuming that I don't go over my plan limit, canceling my iPad data plan and enabling the Personal Hotspot feature will change my total data plan cost from $55/month to $45/month, saving me $120/year.