Once you get that last chance writeup, it's time to start quietly but aggressively looking for another job. I wasn't even given a last chance, just lost 14+ years of employment in the blink of an eye. I don't have to look over my shoulder constantly where I work and have gone from a writeup every 2 years to one in 5 1/2 years, and it wasn't an "I'm going to fire you" writeup so much as an "pay more attention to when you need to clock off for lunch so we don't get penalized" writeup. And generally my company won't fire you, they'll demote you and make you earn your way back up.