Roth TSP vs Traditional TSP

For most military members, Roth TSP is better. Your taxable income is already low because BAH and BAS are tax-free. You're likely in the 12–22% bracket now. In retirement, income will likely be higher = higher bracket.

Paying 12% now via Roth beats paying 22%+ later on traditional withdrawals. Exception: senior officers already in 24%+ bracket may prefer traditional.

Gov matching always goes to traditional TSP regardless of your election. You can split contributions between Roth and traditional.