Pretty much the only people who depend on Social Security alone are people who couldn't afford to save through their lives. Medical emergencies, putting kids through college, etc. My grandfather had a good union job his whole life, and lived frugally, but when he was diagnosed with Parkinson's that was the end of his savings...even with VA medical care (which was awful, BTW).

I'm lucky that I've been able to start saving young, but if I had a kid or two, I'm not sure if I would be able to do it.