By Chip Castille, Managing Director, BlackRock

Let's say you're 25. Close your eyes for a moment and try to imagine what it would be like to be 75.

You couldn't do it, could you? What you may not realize is that when your parents were 25, they also couldn't imagine being whatever age they happen to be today. That's why asking you to save money for your retirement is like asking you to give money to a stranger.

So let's think about this in a different way. Start by assuming that you will enjoy pretty much the same things 50 years from now that you do today. You may be older, but you are still you. If you like going out for a beer, burger and a movie today, the odds are you will still enjoy it 50 years from now.  So how much will it cost the future you and what do you need to do to ensure that you will still enjoy yourself?

Let's look ahead by looking back. Based on a little web research, I found that in 1964, a movie cost \$1.25, a beer cost less than a dollar, and a burger and fries in a midrange restaurant cost around \$1.50. This inflation calculator states that US inflation from 1964 to 2014 was 4.12% per year.  So let's run the numbers and see if that rate of inflation sounds about right:

That sounds reasonable enough. You could spend less and you could spend more for your night out in 2014, but this quick calculation tells us that we are in range. So while we all know that past performance is no guarantee of future results, let's use the same inflation rate to ballpark the future cost of a night out:

It may be depressing to think that an evening that costs less than \$30 today could cost your future you around \$200 in retirement. It shouldn't be, because there is potential good news as well. The good news is time is on your side - if you use it.

If you put aside the price of a burger, beer and movie today in a tax deferred retirement account, and your investment keeps pace with inflation (in our projection, a 4.12% annual return) you will have what you need for your night out in 2064. But it gets better.

According to this calculator, the average annual total return for the S&P 500 for the last 50 years was 9.7%. That's more than twice the rate of inflation.  So someone who put aside half the price of a burger, beer and movie in 1964, invested in something that approximated the total return of the S&P 500 and let time do its work, would have more than enough for their night out in 2014. If they had put aside the full price, they may have enough to bring a date.

You will still be you in the future. Saving for retirement isn't an abstract exercise. It's making sure you can still do the things you enjoy even after you've stopped working.  And the more your investment return outpaces inflation, the greater "discount" you can get on your future night out. You will be thanking yourself later.

Chip Castille, Managing Director, is head of the BlackRock US Retirement Group.  You can find more of his posts here.

Investing involves risk including possible loss of principal.  The S&P 500 is short for the Standard and Poor 500. It is a stock market index that seeks to represent the whole stock market. It tracks the 500 most widely held stocks on the NYSE.  Index performance is shown for illustrative purposes only.  You cannot invest directly in an index.