As the editor of the Smartphones blog on TechRepublic, I frequently receive emails about mobile news, trends, hardware, applications, and more. Most recently, I was contacted by NerdWallet, because they’ve written about a topic that everyone is interested in — that is, what’s the best data plan for your smartphone?

NerdWallet’s post compares data plans from four major U.S. carriers: AT&T, Verizon, T-Mobile, and Sprint. Sure, Sprint claims to have unlimited data plans for new subscribers, but that’s only if users are consuming data within the Sprint network. T-Mobile also advertises unlimited data plans, but they bottleneck devices after a certain point. Verizon no longer offers unlimited plans for new customers, and since data overages can be extremely expensive on Verizon and AT&T, it’s important to get the right plan for your needs.

How much data do you need?

Here’s a quote from NerdWallet:

According to the Nielsen Company, the average data usage per U.S. smartphone customer was 606.1MB (or 0.59GB) per month in the most recent period for which data measurements were available. Frequent web surfers will use about 30MB of data per day, equaling less than 1GB per month. Those who use their smartphones for heavy streaming (on Pandora, for example) find that they average less than 2GB of data usage per month.

This means that unless you are streaming around 10 YouTube videos per day, every day, your data usage will be much less than the average carrier’s monthly data plan.

How much does data cost?

NerdWallet also included the following table, which broke down the plans into cost per penny and cost per YouTube video streamed.

Average Plan AT&T- 3GB Verizon- 2GB T-Mobile- 2GB Sprint- Unlimited
Cost $30.00 $30.00 $30.00 $40.00
Cost/MB $0.01 $0.015 $0.015 Unlimited
Cost/YouTube video streamed $.13 $0.22 $0.22 N/A

Other factors

IT professionals also need to consider network reliability and speed. In a blog post at iPhoneHacks, they addressed all of these considerations when looking for the best data plan for the iPhone 4S. AT&T boasts faster speeds, and Verizon has the largest 3G network. Ultimately, they recommend that you find out what coverage is in the area of your work and residence before you sign on the dotted line with a specific carrier.

What data plan is best for you?

Of course, this will depend on your individual needs. Fortunately, data plans are flexible, and you can always call your carrier and change your plan if you find that you’re using more data so that you avoid expensive overages. NerdWallet also recommends a few mobile apps that will help you track your data usage, including DataMan for iOS and DroidStats for Android.

What things are most important to you when selecting a data plan? Which carrier do you think provides the best plans, taking into consideration pricing, speed, and reliability? Share your opinion in the discussion thread below.