I think it's not always the best to immediately update your wallet software. Personally, what I do is that I read release notes and news. There have been cases when update had some bugs and was dangerous. For that reason, I always wait a little and if I don't hear complains, then I update the software. Of course that highly depends on release notes because sometimes you need to immediately update your software because of critical bugs in current version.

I'm afraid antiviruses spy on you, especially free ones. Instead, I would use Virustotal to check whether websites I visit are safe or not and I would also check some files there too.