Netflix Lets You Downgrade Video Quality So You Don't Hit Bandwidth Caps
After you're logged into your Netflix account, just go into https://account.netflix.com/HdToggle and select from one of three options. "Good quality" at up to .3 GB per hour, "Better quality" at up to .7 GB per hour, and "Best" at up to 1GB per hour or up to 2.3GB/hr for HD.
Recently AT&T added on a 150 GB cap for DSL users and a 250 GB cap for U-Verse customers. Users still report getting a blank page when they try to look at the "bandwidth meter" promise by AT&T, but if you're a heavy Netflix and data user and start to see fees for overages on your bill, downgrading your Netflix stream could help you stay under the threshold.