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.
I had a question today, and I thought it was a good one: How do I change my Thrift Savings Plan (TSP) contribution? Easy, peasy! Just log in to your MyPay account. On the main menu, one of the options is Thrift Savings Plan. Click on that, and it will take you to a form to make adjustments to your TSP contributions.