That is the thing we suppose to do but only techy people who able to do this while others don't care about it and they mostly receive the consequences due to ignorance. Even we do much care of our PC and install blocking apps, we can't still assure that everything will be okay and totally safe as these apps couldn't give 100% safety on your PC. Some leaks could be considered especially when accidentally clinking links that contain malware or virus.
Well, the best way is not to save important information to our PC or laptop, especially when it includes private keys and bank accounts.
You'll find that the more technical people will avoid anti viruses for the reasons I mentioned above. I actually see anti viruses to be more tailored towards those that don't know much about computers or using them safely. For example, and I do hate giving this an an example as it comes across as stereotypical, but it's not meant to be that way; a older generation person that hasn't had much interest in computers, will likely be more inclined to use anti virus because they don't have the knowledge to secure themselves. However, while there's nothing wrong with this approach, there's definitely a element of risk here, since that person will likely assume that they're safe from all attacks, and therefore will be more complacent, when in fact they aren't completely secure.