Age 66 may not seem like the same milestone age 65 is. But if that's how old you'll be at some point in 2020, here are a few important things to be aware of.

1. You can collect your full Social Security benefit

Your Social Security benefits are calculated based on your lifetime earnings, but you're not entitled to your full monthly benefit until you reach full retirement age, or FRA. That age isn't the same for everyone; it's based on the year you were born, as follows:

Year of Birth

Full Retirement Age

1943-1954

66

1955

66 and 2 months

1956

66 and 4 months

1957

66 and 6 months

1958

66 and 8 months

1959

66 and 10 months

1960 or later

67

Data source: Social Security Administration.

If you're turning 66 in 2020, it means you're reaching FRA for Social Security purposes and can claim your monthly benefit in full. In fact, Americans born in 1954 are the last ones to have an FRA of 66; those born in later years have to wait longer to collect their full benefit.

That said, if you don't need your Social Security income right away, you can always hold off on claiming it and accrue delayed retirement credits that boost benefits by 8% a year, up until age 70. With an FRA of 66, you have the potential to snag a 32% increase on your monthly benefit that will remain in effect for the rest of your life.

Smiling older man sitting against tree

Image source: Getty Images.

2. You can work and collect Social Security,  but it may affect your benefits

Workers who earn an income from a job and collect Social Security prior to reaching FRA (you can file as early as age 62) risk having a portion of their benefits withheld if their income exceeds a certain threshold known as the earnings test limit. Once you reach FRA, that issue goes away -- you can earn as much as you like and still receive your monthly benefit in full. But in 2020, those who claim Social Security ahead of FRA will have $1 in benefits withheld for every $2 they earn above $18,240.

There's an exception, however, if you'll be reaching FRA later on in 2020. In that case, if you work and claim Social Security before FRA, you get to earn up to $46,920 without impacting your benefits. From there, you'll have $1 in Social Security withheld for every $3 you earn. And any money that's withheld initially is added back into your benefits once you reach FRA.

Keep in mind that claiming Social Security before FRA results in an automatic reduction in benefits. This is not the same as the portion of benefits that gets withheld for working and filing before FRA. If you're still working and are turning 66 at some point next year, waiting until FRA to file could really pay off.

3. You're eligible for Medicare coverage right away

If you're turning 66 and haven't yet enrolled in Medicare, you should know that you're eligible for health coverage under the program as soon as you're ready for it. Medicare eligibility begins at age 65, but if you're still working at that point and have health insurance through a group plan from your employer, it often pays to forgo Medicare coverage (or at least Part B coverage) until you separate from your employer or your access to your group plan is taken away. But if you're planning to retire at 66, and therefore won't have health insurance through a job anymore, then it pays to enroll in Medicare right away -- both to avoid a gap in coverage, and to avoid penalties for signing up for Part B too late. Keep in mind that if you get an extra year of employer health coverage under an early separation agreement, Medicare does NOT consider that employment-related health care. As such, penalties for enrolling late in Part B could apply.

If you sign up for Medicare and Social Security at the same time, you'll have your Part B premiums deducted from your Social Security benefits automatically. If you choose to just get on Medicare and delay Social Security, you'll need to pay those premiums yourself.

Turning 66 is something to celebrate -- but it's also an interesting age from a retirement perspective. Keep the above points in mind, and with any luck, you'll set yourself up for a financially sound year, all the while setting the stage for a financially secure retirement.