Keeping track of data usage, particularly when roaming abroad, is essential if you want to avoid nasty surprises when the bill comes in. Inclusive packages at home are now more generous than they were only a year ago–typically 3 or 5GB per month compared with a miserly 20 or 80MB previously. And out-of-bundle usage is charged at as little as £15 per gigabyte on Vodafone, which is reasonable at the moment.
Vodafone have a handy data usage calculator to give you an idea of how much you are likely to use in a typical month.
Even so, if you are doing lots of downloading, it is possible to top 3GB or even 5GB within a month. Abroad, though, it is another matter. With some carriers fixing roaming rates of to £7.50 a megabyte (£7,500 per gigabyte!) the potential for serious financial loss is there. We have all read horror stories of data users returning from abroad to find bills in the tens of thousands. It sounds daft, but it is easy to see how it can happen.
Vodafone have a new 24-hour bundle which kicks in if you use data while abroad in most European countries. This costs £10 per day and has a "fair usage" policy of 50MB in the 24-hour period. This is a welcome development and it means that usage is capped provided you keep an eye on downloads. If you go over the 50MB you are charged at £5.20 per megabyte (a staggering £5,200 per gigabyte). Rates outside Europe are even higher and it is essential to familiarise yourself with your carrier's price list before venturing abroad.
If you have a data contract, it is absolutely essential to know what you are using. Unfortunately, the carriers do not make this easy. I am familiar with Vodafone, for instance, and the Mac software is a mere shadow of the package offered for PC users. When loading the software you do get a panel showing usage at the last session and total usage to date (which can be reset) but once you go to connect you cannot retrieve this panel for referece. Typically, you don't see it again until you have reconnected the modem for another session; and that can be many thousands of pounds too late.
I am therefore indebted to Macworld for pointing me in the direction of a free program called CheetahWatch which provides a running monitor of usage and also adds an easy connect/disconnect option. I agree with Macworld that this utility is an absolute must if you have a data contract. I downloaded it before the weekend and have found it to be reliable and very informative. It provides you with signal strength, type of network (GRPS/WCDMA/HSDPA) as well as traffic watch and connection watch. With CheetahWatch you can feel in control and know exactly what you are letting yourself in for, just so long as you know exactly how much your service provider charges.