It's Time to Stop Buying the Capacity Crisis Myth > Siri is causing capacity problem on wireless networks

If you use Siri 2-3 times per day at an average of 63KB per instance, you might expect to use 126KB to 189KB per day, or 3.7 to 5.5MB per month. For 4-6 times a day, that might come out to 252KB to 378KB per day, or 7.4 to 11MB per month. If you use it 10-15 times per day, you might end up using 630KB to 945KB per day, or 18.5 to 27.7MB per month.

Good thing only one person owns a iPhone. Imagine what would happen if millions had one and used it at the same time.