Money contributed to the TSP is put into a retirement fund automatically, but you should ensure it’s invested optimally for you. This is less of a problem now; previously, TSP contributions were invested by default in the G fund, the most conservative fund. Younger service members who didn’t realize this until later lost out on potential growth. As of January 1, 2018, contributions for new TSP enrollees default to an age-appropriate Lifecycle Fund, which is a mix of assets that rebalance over time based on the person’s age. However, participants can manually invest in specific funds with differing levels of asset allocation and risk.