If I were in your shoes, I'd do projections for retiring today, +1 year, +2 years, +5 years, +10 years, etc. Maybe a few more intermediate values. Then you'll

If I were in your shoes, I'd do projections for retiring today, +1 year, +2 years, +5 years, +10 years, etc. Maybe a few more intermediate values. Then you'll have a better idea of how managable it would be if your career was killed, and how much you need to worry about it. But given they're offering an increase in pay, and training, chances are the need is real and may last longer than you're willing to do it. Also, after you've migrated the system, you'll have useful knowledge for that company, in that you probably deeply understand their business logic. And you'll gave useful knowledge for other companies, in that they want to leave VMS behind too.