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.
There are some reasons why you might not want to borrow from your TSP, even if you have the option. 1  When you borrow your pre-tax dollars from your TSP, you have to pay yourself back with after-tax dollars. This means to pay back $100, you may actually have to earn $128 or so.