Unfortunately, I think most simply don't think about it.
You should be stashing money away, but you should mostly be making alternative investments that give you more passive income. Real estate is one investment, this needs care and attention but it is not a full time job by any means. It allows you to build equity while maintaining an income. Which is much better than just putting money in the bank, which will make you almost no money.
At the moment all my profits pay the bills and get my wife through school but as I build more income I plan on setting a percentage of profits aside for retirement. Maybe 10% at least to start and increasing it as I build the company.
Start saving as much as you can as early as you can. Compound interest is your friend. You can never retire with too much money. I'm 54 and I started saving at 18. I sacrificed on some things but I do not regret it one bit.
I've put most of my money back into my businesses. I do have a SEP that is doing well and I own a few pieces of real estate. I don't plan on retiring (exactly) but I do hope to spend a little more time goofing off.
We paid $200 per month for my husband's mutual fund with USAA. My Grandfather manages all our retirement accounts - all the grandchildren strive to retire like my grandparents. If you were in the military I highly recommend looking into USAA retirement plan. These past 15 years we've put away a nest egg that we won't/can't touch until we're 65 (32 more years!!!). The least amount you can put in is $50 per month. I started out doing international stock higher risk greater gain. As I get closer to retirement I slow change over to something more secure.
It isn't easy... Matter of a fact it is hard... But the rewards of living comfortably once retirement hits is what I strive for...