I took mine at 62, my wife is waiting until 65. Here's why.
After I closed my store at age 62, I had no effective income (other than what I might bring in by EBay sales, etc.) My wife, a home health physical therapist, is still seeing patients and is still earning a "normal" income. Her income is sufficient that I don't need to bring anything in to pay the bills.
Let's start with her's. If she had taken it at age 62, and still earned a significant amount, the penalty taxes ($1 for every $2 in income) would have eaten up her SS. There was no point in her taking it. After age 65, she can earn as much as she wants, and there will be no penalty taxes on her SS.
Now, mine. That 14 year period mentioned above seemed to work out for me, too. If I had waited until 65, I would have to collect until age 79 in order to merely break even. I probably won't live that long, but, even if I do, we have another plan.
Since I don't need the income now, what I did was take the early amount, then shift it to an investment account. I've made some decent investments with this money, and it has grown and is producing income. So, at age 65, I have my SS plus the income I earn on the investments made in the previous 3 years; and I still have the principle from those 3 years, plus whatever growth there may be in the investment value. The combination puts me way over the top on waiting until I was 65. I can't remember the exact number I calculated at the time, but based on conservative estimates of the investment income, and barring a complete collapse of the market, I would have to live until into my 90's to break even, and even longer to get ahead.
There's a risk associated with my investments, but an even greater risk that I wouldn't live long enough to break even. This way, the money's in the bank, so to speak.
To make it easier to keep track and make sure the investments do what I want, I started a separate Scottrade online account for the SS money. I track it in Quicken, and can get an instant report on my ROI.
I should be pretty much done with building our house, etc., once I get past 65, and if I choose, I can go back to earning as much money as I can, without incurring the penalty taxes on the SS income.