How often should i run my anti-virus and spy bot search and destroy ?

I use avast which is a free one So i can not have it set to run it self every so often

How often should i run my anti-virus and spy bot search and destroy ?computer security

Min. of once a week

I suggest every other day

How often should i run my anti-virus and spy bot search and destroy ?free spyware remobal

best way is to check every couple of days but if you have a free one that you can't regulate check it every week.
If you downloaded Threatfire (free) this gives you an early warning sign of any problems with viruses or spyware so then if you are not getting any messages from Threatfire you could just do weekly antivirus and Spybot tests. You can run Threatfire with your normal antivirus as it works in a completely different way and just gives an extra level of security and early warning signals.
every week
Depends on your surfing/download habits.

2-3 times a week.
spybot updates weekly so best to update it than reboot and do a full scan.

anti-virus will depend on your surfing habbits, few times a week should do.