What are the disadvantages of receiving soc at 65 rather than receiving it at age 66 which is my full retirement age..

One important fact that a person should know, but cannot know, when deciding at what age to begin receiving Social Security benefits is when the person will die.

When a person elects to receive SS benefits before the person's "normal" retirement age, the person received a reduced level of benefits for the rest of the person's life. When a person delays receiving SS benefits until after the normal retirement age, the monthly benefit amount is increased.

If a person knows that the person will live a long time, it may be economically advantageous to delay receiving SS benefits as long as possible. On the other hand, if the person knows that the person will die soon (perhaps even before the normal retirement age), it would be better to collect SS benefits as soon as possible.

Since no one really knows when a person will die, deciding when to start getting SS benefits to maximize the total benefits received is guess work. One can look at one's relatives' longevity to guess at how long one will likely live.

You can use the free benefits estimator available at www.ssa.gov to see when to apply for benefits may be better for you. That site also provides a lot of useful information.