We dont get this question because not all of us have that option.
I dont know how much you know about this but let me assure you dont know.
For 2017, if you earn at least 5200, you are credited for every four quarters for entire the entire 2017. It does not matter when you earned it( all in one month out throughout the year). You need 40 quarters of coverage to be fully insured for SS benefits in your working life. So, if you have at least one quarter from age 21 to age 62, you are fully insured. So you can manage your quarter as you want.
If you have the option to opt in and out, why not opt in when you meet all your credit for each quarter, and then opt out.
But remember, some SS benefits are available to "currently" ( not necessarily fully) insured individual. Currently, insured workers are those who have at least six quarters credit out of last 13 years.
In my personal opinion, I would not opt out. It is a very small amount for such a comprehensive benefit and insurance you receive. You are paying now because when you are old, you can't pay that when you retire.
SS pays for:
Retirement, Disability, family benefits, Survivors benefits, and Medicare
This is the best Risk management. If you ever have to liquidate your RE investment for health reason, law suites...., you know you are covered at old age.
I would not contribute to a retirement account and rather invest when you get started in the RE, but not FICA.