If you use Avast, either as your primary or as your secondary AV, updating it is a good idea. One critical improvement is that virus database updates happen more frequently now. There’s no such thing as too frequently when it comes to database updates.
I noticed this week that even governments are falling to PDF-based vulnerabilities. The best way to handle PDFs is to translate them to something else, then display them, the way Firefox does now. You lose some fidelity, but you also lose the malware payload.
And whether that’s an option or not, you stand up defense in depth behind it. If I traveled back in time to 1998, and told my 1998 self that in 2013 I would be advocating the use of two antivirus engines and a third-party tool that checks for updates in real time, my 1998 self would say, “Security in 2013 is that bad?” And I don’t think my 1998 self would believe it. And, yes, my 1998 self would say, “What a waste of computer resources.”
But even with all three of those tools running right now, my CPU usage is well under 10 percent, and my memory usage is at 34% with Firefox open with my usual 14 tabs, and a Word document open. And this system isn’t anywhere near high-end. Even a modest PC these days has plenty of idle resources to run security tools.
Then again, if you don’t have the resources to spare for some reason, you could always uninstall the four horsemen. That’s an option too.