Welcome Ebeneze!
An update basically counts whenever you transfer data from one place to another.
It's like Google Maps. We're the routing. The longer your distance or the more volume you transfer, the more costly it gets.
Thus, the more data you transfer, the more places you connect to each other, the more update quota is being used.
You can at any time upgrade or downgrade your account to match your current needs.
Let me know if that helped!