Speaking from a management point of view, it's not about the financial cost. It's the fact that the company needs to get your job done still. Do you hire someon

Speaking from a management point of view, it's not about the financial cost. It's the fact that the company needs to get your job done still. Do you hire someone else? If you do, you need to deal with issues such as headcount, budget, what to do with them when you return. Look at it from another perspective. If given the choice between 2 equal candidates and you choose the one that's not about to take "leave". It's not discrimination, it's purely you making the best choice for getting the job done. One person is going to start the job right away, one is basically say "hang on, I'll start that in x months".