Our happy household has a number of computers that range in age from 6 months to about 5 years, and they contain a mix of anti-virus and internet security software. I think all the major vendors of anti-viral muck are represented on the desk in front of me.
If I was half sensible, I'd standardise on a single package for the lot and do away with the jumble of crap that we have, because I have found that modern "security" packages are the most confusing collections of shit known to man. We have four flavours of firewall, all of which are so impenetrably difficult to comprehend that most of the features are turned off. The oldest PC has become so slow since the latest version was loaded that it s almost unuseable. Security scans take hours.
I got jack of it this week and removed the "fully featured" package from my laptop and installed just a bare bones anti-virus setup. All the additional firewall crap and phishing stuff and kiddie friendly garbage has been removed. Funnily enough, the thing seems to run a bit faster now, and I have gone an entire week without swearing at it.
I have come to the conclusion that installing these software packages is like attaching leeches to your testicles in order to ward of evil humours. Sometimes, the idea of having more and more of something (like leeches) is not a good thing. From now on, I am going to make do with less.