I'm in FERS with nearly 20 years in, I had no choice in FERS vs CSRS. Because of the rules for FERS, unless I retire at 62, I will get 10% less a month in my FERS annuity, so I will not retire earlier than 62. The math on Social Security is laughable, unless I decide I really want to stay until I'm 70 - IF there enough money to back up the system when us Busters retire. I do not think Social Security will have enough money to pay back the Boomers on what they put in, and suspect it may run out right when the most long-lived of that group is most in need, and us Busters are in the middle of our golden years (if not earlier).
That leaves TSP as my main source of retirement funds. With nearly 20 years in, I already have a considerable amount of money in my account. G fund frankly does not pay enough to cover inflation. Parking in the L funds during the first 3 quarters of this year, if you are a Buster in L2030 or L2020 due to you later retirement date, who has a considerable amount of money already in the system, you just went back in time to 2003. There is a huge difference between averageing 7% a year (where I was up to the end of last year) to how bad it would have been if I hadn't gone to G during the first quarter of 2008. I am able to enter the market now through payroll and loan deductions (I have a residental and a personal loan outstanding). Because I could move my funds around, my retirement didn't suffer a huge haircut. But anyone with a lot of money in the TSP who parked L 2020 or worse, 2030, and didn't look is in considerable distress now, especially if they paniced in the last month.
I may not have to delaying my retirement yet, thanks to my ability to get out before everything tanked. However, on the longer term, it depends how returns look over the next few years. If the stock market takes a long time to recover, and my assumption of an average of 7% a year returns is wrong, I will have to consider retiring after 62. And how about those who just parked and then paniced at the worst time?
However, even they can recover - because they can delay their retirement. The people you should be worried about are the ones who already are retired and did not expect a negative return on their nest egg. How are they going to recover from a bad Parking L decision??