With all the possible factors: leaving for a better job, falling ill, having a family member fall ill, getting hit by bus, getting poached by a competitor, or t

With all the possible factors: leaving for a better job, falling ill, having a family member fall ill, getting hit by bus, getting poached by a competitor, or taking parental leave -- that last one is hardly even the worst. If you're worried about that, you're not worried enough about real issues.