I write a column similar to this one every January. But I don't mind plagiarizing myself because it contains a very important message for people planning to retire in 2009.

January is a critical month for the hundreds of thousands of potential Social Security beneficiaries who are reaching their so-called full retirement age in 2009. The important message: All of them should at least consider the possibility of filing for their benefits this month, even though they may not be reaching their retirement age until later in the year.

The reason for this early filing timeframe has to do with some quirky and complicated features of Social Security's earnings penalty provisions. Those provisions generally keep seniors who are still working off of Social Security's rolls until they reach that magic "full retirement age." For most people reading this column, your full retirement age is probably 66. (Check out the Social Security Administration's website at www.socialsecurity.gov for a chart listing the various full retirement ages.)

The law essentially says if you are over 62 but under your full retirement age and are still working full time, you are not eligible for Social Security. Specifically, the rules require that the SSA deduct $1 from any retirement benefits you might be due for every $2 you earn over $14,160 in 2009.

However, the rules say that once you reach full retirement age, you are due full Social Security benefits even if you are still working and no matter how much money you are making.

Let's follow an example. Let's say Bob was born in July 1943, which means he'll reach his full retirement age of 66 in July 2009. And let's further say Bob generally makes about $60,000 per year and he plans to continue working indefinitely. Based on the earnings penalty rules I briefly outlined above, Bob figures he must wait until July (his full retirement age) to begin collecting his Social Security benefits. As I said, at that magical point the earnings penalty rules no longer apply and he can get his Social Security.

But here is why Bob should check into applying for Social Security in January. Congress set up a more lenient earnings threshold for the year you reach your full retirement age. Specifically, it says you can earn up to $37,680 between January and the month you reach your full retirement age and still get Social Security benefits. And even if you earn more than $37,680, you lose only $1 from your benefits for every $3 you exceed that threshold. Continued...