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.
Once you retire, many financial planners will encourage you to roll your TSP funds into a tax deferred option that they will be happy to sell you. It may be an IRA, a deferred annuity or some other type of investment. You may not know that you can roll money into your TSP from certain accounts. Both current employees and retirees may roll money into the TSP. Money can be rolled into the TSP from a traditional IRA, SIMPLE IRA and/or an eligible employer plan. Rollovers are not allowed from Roth IRAs or Roth 401(k)s. I expect that once the TSP introduces the Roth TSP (currently planned for April 2012), that the Roth TSP will accept rollovers from Roth IRAs and 401(k)s.