It is a lot,something that the Finance types totally ignore. First of all, if someone leaves who is skilled, it usually takes a while to hire someone who is a fit, someone who has the skills and personality to fit in, so right there you are losing time, plus then once you get someone, they have to learn. Not to mention that likely you will end up paying a replacement more, and if you use a headhunter, that can be a significant cost, as much as a years salary. I have had battles over a 5k raise, and by estimates replacing the person cost the company about 80k in fees and lost productivity, but try telling that to a finance type prod of how they saved the company money.