After you first signed up for a mobile data plan with your carrier, odds are you kept a close eye on your usage to make sure you didn't bump up into the forbidden overage zone. No matter the plan, they tend to get expensive really quickly when you exceed your monthly cap. This is particularly easy to do when traveling.
International travel requires planning to get inexpensive data connectivity, but even domestic travel should be given some thought before heading out the door.
I pay a healthy monthly fee for my 10GB of pooled data. It's admittedly too much, but I depend on having connectivity no matter what so I fork out the money. I have three tablets drinking at the data trough.
I keep an eye on my monthly data usage, although since I have a healthy cushion I only do it every few months. When I check it I sometimes spot an anomaly in my usage patterns, and can make adjustments as necessary. One analysis showed a marked jump in my monthly usage when I got the Kindle Fire HDX. Seems it uses a lot more data than the iPad mini it replaced.
In the six month usage chart above, one anomaly jumps right out. My data usage in May was double what it usually is in a month. It was nowhere near my cap given my large allotment, but it was quite a bit higher than usual.
Turns out I made a couple of short trips that month, and I relied almost exclusivey on my mobile broadband. My data usage was higher on those trips, much more than I expected it would be.
These trips combined were only five days, so I'm surprised data consumption was double what it normally is over the whole month. That's not that many days, plus I regularly use the mobile broadband for two - three hours per day when I'm at home.
There may be something else at play contributing to the much higher usage, but I don't know what it could be. Maybe roaming factored into it, causing some constant polling. I wouldn't expect that to be the case, but consumption was so much higher that there must be a reason.
I can only imagine what my monthly usage would have been if I had taken a two - three week vacation. It could have pushed me up near that generous data cap, even over. And that would have been an unexpected expense.
It's probably a good idea to plan on significantly higher data usage when traveling. If you routinely get near your monthly cap it may be worth bumping it up before leaving. You may end up not needing the extra data but you won't be surprised when you get back.