Postfix keeps running even if one Postfix process dies; Windows requires that someone restarts the service.

Like all software, Qmail can survive only when it keeps up with changing requirements.

The challenge with Postfix, or with any piece of software, is to update software without introducing problems.

In a previous life I wrote the software that controlled my physics experiments. That software had to deal with all kinds of possible failures in equipment. That is probably where I learned to rely on multiple safety nets inside and around my systems.

For many people my software is something that you install and forget. I like to keep it that way.

I don't expect an overnight change of all desktops to what the US Military used to call B3 level security. And even that would not stop users from shooting themselves into the foot.

Defect-free software does not exist.