Ask HN: Do You Use Antivirus?

I have a general impression that antivirus software is an old-world solution for device security. I don't use it personally. But I was asked about it recently by a relative, and realized I didn't have a strong case for not using it. Here's what I've heard: - AV primarily served as a fast-security-update mechanism before OSes and browsers provided frequent updates - You don't really need it if you follow other good practices like treating links in emails with high suspicion, not running binaries from the internet that you don't have an enormous amount of trust in, and keeping your software up to date - AV itself can actually be an attack vector because of the high permissions it's given I, however, am not a security expert. Can anyone with a real security background weigh in? Does anyone on HN use antivirus software, and if so, why? Are the answers different for different OSes (including Android)?