Sick Leave for English Teachers
Koreans do not take frequent sick leaves due to illness. But exceptions are there for foreign teachers. The employment contract that is signed between the school and the ESL teacher includes 3 sick leaves in a year. In this context it needs to be mentioned that these are not extra days that you can take off. If you are taking sick leave, then, do remember that you will be visited by your employer and he or she will take you to hospital. So, you cannot take sick leave for short vacations.
It is thus implied that it will not be a good idea to take sick leave until and unless you are seriously sick. Bad mood day or hangovers are actually not well accepted as excuses for missing teaching classes.
Legally the school authority has the right to deduct your salary for your absence if you have not produced official proof from a doctor. Usually the employers do not ask for this official proof until and unless someone has a record of taking single sick leaves.