Data limits are the bane of many people's existence. They're a necessary evil but always seem to run out just when you need them and then you get hit with crazy excess charges or 'shaping' that cuts your data flow to a trickle. Galaxy devices make it nice and easy for you to set a mobile data limit to avoid running out of data entirely or bringing on some bill shock at the end of the month.
On the Galaxy S3 just hit Settings > Connections tab > Data Usage > Set Mobile Data Limit and enter whatever data limit you like before you get a warning. Our screenshots are an international Galaxy S3 running Samsung's Android 4.3 firmware.
On the Galaxy S4 it's exactly the same path: Settings > Connections tab > Data Usage > Set Mobile Data Limit. Depending on what version of Android you have or what custom ROM you might be running, the path may be slightly different. Our screenshot is an international Galaxy S4 running Samsung's Android 4.4.2.
The Galaxy S5 is slightly different due to the new TouchWiz, but it's just as easy: Settings > Quick Settings > Data Usage > Set Mobile Data Limit. Our Galaxy S5 is, of course, running the straight-out-of-the-box Android 4.4.2 firmware.
Note: You will only see the Set Mobile Data Limit option if you have a data enabled SIM card inserted.
Mobile data limits can be set on any device running Android 4.0+. Just look for the Data Usage section in your Settings.
Do you use this feature? What other ways do you keep track of your data usage?