To calculate what level of data limit you need, you must consider what you will do with your mobile broadband access.
You might need to break this down into per day or per week usage and then collate to get an overall view for the month.
There are a number of online mobile broadband usage calculators available to help with this process, but as a guide things to cover might include-
How many emails do you send and receive?
How many minutes do you spend on Instant Messaging?
How many minutes do you surf the web?
How many minutes of music files do you download, including albums and playlists?
How many minutes of video or films do you download, including YouTube clips?
How many games or software updates do you download?
How many photos do you upload or download?
As a very rough guide, consider the following data sizes:
1MB =
100 emails without attachments or
3 emails with attachments or
1 email with photo attached or
1 hour on Instant Messanger
80MB=
8 hours surfing the web or
20 MP3 music downloads, 3 minutes each or
2 video downloads, 5 minutes each
The amount of data you need per month can then be calculated. You can quickly see that if you limit yourself to 1GB you’ll be limited on what you can do.