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.
Decide how much to invest. You can invest up to $18,000 in the TSP in 2017, plus an extra $6,000 in catch-up contributions if you're 50 or older. Since contributions are pre-tax, investing the full $18,000 only reduces your take-home pay by $13,500 if you're in the 25 percent tax bracket.