Yeah, like 30 or so years from now for most people.
As a long time investor (since 1986), it simply doesn't matter what the markets close at TODAY. Or TOMORROW. Or the next day. I rode out the 1987 crash, the dot.com bust, the housing bubble, even Obama.
In fact, I remember my co-workers back in 1987 (1987!) fretting about their 401k's during that year's crash. Back then, Japan was basically about to buy the United States and put us all into servitude and a decades long recession. According to the "experts" of the time.
I've been in the stock market and investing part of every paycheck since 1985. I remember the crash of 1987, I was working at a small software company and worried I was going to lose my job (I did.) I managed to find another in a few short weeks and made more than the job I was riffed from.
Here I am all these years later and I'm not worried. Whatever's going to happen is going to happen. Invest responsibly, know how to manage your assets to protect yourself and if one cannot do that find a good investment advisor (fee based) and don't react emotionally to the markets.
Warren Buffet said it best: when others are panicking, you should be buying.