Whoa, unless the bonus is astronomical, you would really need to question the offer, especially if relocation is involved. The longest earn-out I've ever had on a hiring bonus was 6 months, even then I left within 5 and didn't have to pay it back. The amount of things that can cause you to leave a job or be fired over two years creates a huge risk, and creates an incentive for your employee to fire you on your 23rd month.