how often does avast update??
Generally two times a day!
This page will give you an overview of how often it is updated: http://www.avast.com/eng/vps_history.html
Here is describe what the VPS version number means: http://forum.avast.com/index.php?topic=3878.0
The minimum intervals currently are like this:
Free AV: 120 minutes ( = 2 hours)
Pro AV, IS: 15 minutes
ok thanks ;D