Age-. The general rule in the industry is that once an A/C unit reaches 10-15 years, the idea of replacing the unit is usually a much better investment than putting money into an older system. If your system is at this threshold, it's usually wise to begin expecting, not wondering, when the system will fail.
You can keep the money in the TSP after you leave your federal job to benefit from the low fees, or you can roll over the money into an IRA or a new employer's 401(k), 403(b) or 457.
With a direct rollover, your pension funds escape being taxed until some time in the future when you begin to withdraw from that rollover account. Caution: should you receive a check and it is for only 80% of your retirement funds, you may wind up paying taxes if you do not take some immediate and decisive action.