Can you predict that Susie on your team will fall ill for a few week. I can tell you, if you have a relatively long project, it's worse than that: Susie (or so

Can you predict that Susie on your team will fall ill for a few week. I can tell you, if you have a relatively long project, it's worse than that: Susie (or someone else) will probably quit. Better take that into your estimate calculation. Remember, estimates are an outer bound; if you finish early, that's ok.