[E. Pluribus Unum]

Even a justified shooting takes years off a person's life.

It is the very last thing you ever want to do.

[Pollster1]

Even a justified shooting takes years off a person's life. It is the very last thing you ever want to do.

I would say it is the second to last thing you ever want to do. Choosing not to shoot when you need to shoot is the last thing you ever want to do (and if you make that mistake, it is likely to be the last thing you do).

[dainbramaged]

Even a justified shooting takes years off a person's life.
Years back I had a drunken maniac on my front porch at 3AM saying he was going to kill me. I also had a .45 revolver aimed at his chest from four feet away - luckily the cops came down the street at that moment, distracted him and I was able to shove him down the stairs where they grabbed him up. Very glad I didn't have to pull the trigger.