Those who leave the military at 20 years are unlikely to be able to survive on just a military pension, since depending on whether you’re on the legacy plan or new plan, your payments are only equivalent to 40-50% of your base salary. You’d have to stay in until 40 years on the legacy plan to get your full paycheck, and those on the BRS can never achieve more than 82% given the TSP component. However, since the average retiring service member is in their 40s, it’s common to pursue another career and earn additional retirement benefits. You can earn a whole additional retirement pension if you work as a federal employee. Or if you go to the private sector, you can sock away money in a 401(k) or IRA that you can use to supplement your military pension.