If you are going through serious health conditon and if there are very less chances of you living next few years as per doctor then taking Social Security will be best for you.
If you have debts and if you are unable to increase your earnings or take money from savings, you should consider taking Social Security payment as soon as possible.
If you are going though financial emergency or crises and if you are at leat 62 then it makes a sense to sign up for the Social Security early.
If you are married and both of you are eligible for Social Security Payments then its best that lower earning partner collect soon and high earning partner delay the claim of Social Security.
The Social Security gives you 8% guaranteed per year for each delay claiming full retirement age. If you are confident enough that you can beat the yearly 8% return then you can take Social Security Payment early and invest it.