Netflix's apps for both Android and iOS have already received updates that bring with them a new and very useful feature. There's a new option to be found in the App Settings section, namely Cellular Data Usage.
This basically lets you change the bitrate of your video streams for when you're watching Netflix over your mobile data connection. There are a few options to pick from. The default is Automatic, which is around 600Kb/s, or three hours of streaming per gigabyte of data used.
If you don't like this setting, you can go with Low (that's 4 hours per GB), Medium (2 hours per GB), or High (1 hour per GB). Additionally, you can indicate that you have an unlimited data plan from your carrier, in which case you'll get the highest possible quality. And finally, you can also turn streaming via cellular data off entirely - if you do this, you'll only be able to watch Netflix content over Wi-Fi.
The new feature is available globally, wherever Netflix is. It should help you avoid any unpleasant surprises come billing time from your carrier of choice, letting you tailor the stream's quality to your particular data plan.