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.
When you take a withdrawal from your TSP account, you can't make any contributions for six months, and the money you remove no longer earns interest, so you are at a definite disadvantage. After you determine how much you need, head over to the TSP website and fill out a Hardship Withdrawal form. You will have to justify to the TSP Board that you need the money-no frivolous expenses such as sports cars and designer handbags are allowed.