You could call it broadband mission creep. Once consumers adopt high-speed data services, their data consumption increases quickly. They connect more devices and become semi-addicted to using said gadgets, and then buy even more, which they cheerily connect. They stream more videos, become experts at the likes of Minecraft, access the cloud and indulge in heavy data-driven activities. They have only a vague idea of the details of the current plan they’re paying for.

Need. More. Data.

“Managing consumer expectations is extremely important in a highly competitive marketplace,” Brett Sappington, director of research at Parks Associates says. “If consumers are caught by surprise with additional charges, they will be likely to switch providers out of frustration.”

So is an unlimited data plan part of the answer? AT&T is one of the ISPs that looks like it thinks it is.

The company announced yesterday that it will update its U-verse home Internet plans with more data for all Internet customers, including an unlimited data option available to home customers.

“Today’s Internet speeds are faster than ever and we’re all using it to do more – streaming video, gaming, accessing the cloud or uploading videos and photos,” Bob Bickerstaff, VP of data and voice products at AT&T Entertainment Group, says. “That’s why we’re going to provide U-verse home Internet customers with more choices and more data.”

On May 23, the company will introduce a new unlimited data option for its U-verse home Internet subscribers. AT&T customers who have only the U-verse home Internet service can add unlimited data for $30 more a month. Customers with U-verse home Internet and either DIRECTV or U-verse TV service, and who pay for those services on a single bill, will automatically receive unlimited data at no charge.

“The unlimited data plan is likely for the uber-data users that far exceed their data allowance each month,” Parks’ Sappington observes.

Also effective May 23, AT&T says most of its U-verse home Internet customers will receive an automatic increase in their monthly data allowance at no cost. Those allowances will range from 300 gigabytes to 1 terabyte, depending on Internet speed tier. Home Internet customers use just over 100 gigabytes of data per month on average, AT&T reports.

To tackle the fact that many users don’t have the foggiest about their Internet usage statistics, AT&T offers online tools to help customers manage usage, including a calculator that allows them to estimate the amount of data they might use in the future.

AT&T also reports that on May 23, customer can check their current usage online, which they probably will want to do to avoid any of those dreaded overage fees.

“Each month, we’ll notify customers as their data usage approaches or begins to exceed their data allowance,” AT&T says in a statement. “There will be no charge for additional data during the first three months. Thereafter, we’ll provide customers with additional data as needed in 50 GB increments for $10 each.”

Comcast is also exploring an unlimited data plan and overage charges. More CED coverage of that trial is available here.