This is my 15th year teaching in Baltimore City. I am a second-career teacher and plan to retire in three years. I have taken two sick days in that time. However, the school system operates under a use-them-or-lose-them policy unless you stay in the system for 20 years. That just will not be possible for me, and since 50 percent of all teachers leave by the fifth year, the current system simply promotes the taking of sick leave unnecessarily ("This looks a lot like playing hooky," Nov. 13).