How easy to damage a spindle?

Ok, I would like to preface this by saying: I do everything I possibly can to NOT crash my machine. My Haas VF4-SS is the single most expensive thing I own except for my house. Tools are not cheap and I’m not made of money. It’s not like the boss will write a check to make mistakes go away, cause I’m the one who has to write the check.

That being said…

Ooops. I was running a proven program today, but it stopped in the middle and told me there was a tool compensation error. Should have checked earlier or caught it in a simulation run, but no big deal. So I hit hand jog, hit Z and then proceeded to spin the dial in the positive direction. Nothing happened. Ooops, need to hit reset. No big deal. Hit reset, error goes away. Proceed to spin the dial in the positive direction, and my end mill moves into the positive Y direction instantly snapping the 1/2 EM with about 2.25in stick out. Not a mistake I will likely make again. Should have just hit Z G28 or hit Z one more time.

I have broken bits before, but this is the biggest. After already stating that the obvious solution is don’t crash your machine, my next question is how big of a crash does it take to mess up things? I have heard horror stories of spindles needing replaced. Is this something to worry about? What type of crash does it take for you to worry that damage may have occurred?