Joe wants to know how effective antivirus software is. Leo says it can work, but it really does give users a false sense of security. Zero Day exploits can still nail people within 24 hours of discovery. They can also expose people to more flaws. That doesn't mean Joe shouldn't have one, though, but Leo recommends not buying anything third party. He should stick with Microsoft's own Defender that comes with Windows 10. Ultimately, though, his online behavior is his last, best line of defense.
Leo says that ESET is also one of the best antivirus programs out there, and they don't have any security issues he knows of. He used to recommend them because they were very lightweight and updated frequently. But he really doesn't need it anymore. Microsoft is on the case with Windows Defender. He should just keep his OS up to date and monitor his own online activity. He shouldn't download things from places he doesn't know. He should also make sure not to click on strange links in emails. Be cautious.