While there are a few factors, a significant reason for Congress’s decision to switch was the finding that in the legacy systems, 51% of officers and 83% of enlisted service members didn’t make it to 20 years of service. This means they received no retirement pension. In order to make the military more aligned with the private sector, where employees now often receive employer retirement contribution matches and funds that vest quickly, the government changed plans to make retirement a blend of funding sources. Under this new plan, it’s estimated that 85% of service members will leave with at least some retirement money. However, it does put the onus on the service member to contribute 4% of their own salary to receive the full benefits of the TSP match.