It is very important to have an emergency fund. If you happen to lose your job suddenly; face a medical exigency; a pay cut; or any such unforeseen circumstances, you would need your emergency fund to fall back on. Ideally, you should have at least six months' expenses in the form of an emergency fund. In case you are working in the private sector, where job security is low, you must try to have at least a year and a half's expenses in the fund.