I used to run a dedicated antivirus program, but I lapsed on that too. These days my primary defense against malware is sandboxed browsers, plenty of backups of important files, and just not running untrusted executables. That besides whatever my OS has got running in the background. It feels like antivirus software is a lot less of a thing these days than it used to be. It's usually enough to just be mindful of the applications you're running.