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AT&T just announced new data plan packages for the iPhone, and also announced that users of these plans can purchase data tethering for their phones. Should you switch?

The new iPhone data plans

Before the new plans, every iPhone user was required to buy a $30/month, unlimited data plan. Now, there are two options. For $15/month you get 200 megabytes per month. If you go over, you pay $15 for each additional 200 megabytes used. In other words, if you go nuts one month, you could get socked with overage charges.

The other option is $25/month for 2 gigabytes. If you go over, you pay $10 per each additional gigabyte used. If you are a current iPhone user, you can still elect to keep your $30/month unlimited data plan.

Like always, however, there is an incentive to switch. If you downgrade to the $25 data plan for an additional $20 you can use your iPhone to tether an internet signal to your laptop or other device. In all, you would pay $45/month to have 2 gigs shared between your iPhone and whatever other devices you want.

How much data do you use?

Most attorneys use their iPhones to check email and surf the web. Maybe once or twice a week you will take a look at a YouTube video. For the most part, the usage is limited to web-based applications that do not suck a lot of data.

You can easily check how much data you use by going into Settings>General>Usage. Scroll down to Cellular Network Data and look at Sent and Received. Add the two numbers together to get your total usage.

At the bottom of the screen, it should show “Last Reset.” To estimate your monthly usage, divide your total usage by the number of months since your last reset.

I use my iPhone a lot, and in five months, I have used about 3.7 Gigabytes, so roughly 800 megabytes a month.

Should you switch your iPhone data plan?

The $15/month plan does not provide enough data, and it would be fairly easy to surpass that limit in a month. The $25/month plan provides a lot more, and most users are unlikely to surpass that usage. It would be nice to have the tethering option, but $20 is a little steep just to share the data without additional megabytes.

In terms of attorney-usage, you can do nearly everything from your iPhone, so using tethering seems fairly unlikely. In other words, either stick with the data plan you have, or downgrade to the $25/month option, but do not bother with tethering unless you have some compelling reason to use it.