This Might Be the Biggest Social Security Mistake You Can Make
Seniors get a range of choices for claiming Social Security. You can sign up for benefits as early as age 62, but you won't be entitled to your complete monthly benefit based on your wage history until you reach full retirement age (FRA).
FRA kicks in at either 66, 67, or 66 and a certain number of months, depending on your birth year. You can also delay your Social Security claim beyond FRA and boost your benefits in the process.
Now, age 70 is generally considered the latest age to sign up for Social Security. While you won't be forced to file at that point, you will no longer benefit financially by delaying your claim.
Source Fool.com