You are entitled to a maximum SGLI coverage of $400,000. You can choose for lesser amounts but it should be in increments of $50,000. You have to fill a form SGLV 8286 if you desire to reduce or decline the SGLI coverage. You can even keep any Government or private insurance if you have the optimum amount of SGLI. But your SGLI and VGLI coverage should not exceed the limit of $400,000.