Is it possible to set the update interval manually? e.g. once each day.
How often does avast! check for updates by default?
It checks for updates when you connect to internet and than every 4 hours. This is optimal interval. For each “blank” check (eg when no new update available) it uses only 3Kb of bandwidth so its practically nothing.
You can also use manual VPS update via trey icon anytime you want.
If you have avast! Pro,than you can set update scheduling task for VPS update on desirable time of the day or of the week 
Ok, thanks for the quick reply. 
i think you can customize that… ;)…i never try though
http://forum.avast.com/index.php?board=2;action=display;threadid=1647;start=0
courtesy of tech… ;D
Thanks shgoh for quoting that forum…
But, everybody must remember: do not low the value of the interval of updating (4 hours). This could be trouble for Alwil webpage and, so, for us. If the users use this possibility ‘by default’ probably they would be taken off from the configuration… 
yeah…just leave that setting alone…the default setting works fine…