I have been working at my company for over 15 years. In that time I have gained immense knowledge on the proprietary software that the company needs for everyday operation, and, I'm the only person that knows the system so well. It would take a new comer years to get up to speed.
Recently one of my coworkers that was also here 10+ years quit so I'm essentially indispensable. Should I use this opportunity to ask for a substantial raise (50% increase to salary)? Basically my company is screwed if I quit so I feel like I have a lot of leverage. How would you react if you were the boss?