When individuals earn money, their first responsibility is to pay current expenses such as the rent or mortgage expenses, food and other necessities. Once these expenses have been covered, the next step should be to fund a retirement plan or some other tax-advantaged vehicle.
Unfortunately, retirement planning is an afterthought for many young people. Here's why it shouldn't be: funding a 401(k) and/or a IRA early on in life means you can contribute less money overall and actually end up with significantly more in the end than someone who put in much more money but started later. (To see how this works, check out Why is retirement easier to afford if you start early?)
How much difference will funding a vehicle such as a Roth IRA early on in life make?
If you're 23 years old and deposit $3,000 per year (that's only $250 each month!) in a Roth IRA earning and 8% average annual return, you will have saved $985,749 by the time you are 65 years old due to the power of compounding. If you make a few extra contributions, it's clear that a $1 million goal is well within reach. Also keep in mind that this is mostly interest - your $3,000 contributions only add up to $126,000.
Now, suppose that you wait an additional 10 years to start contributing. You have a better job and you know you've lost some time, so you contribute $5,000 per year. You get the same 8% return and you aim to retire at 65. When you reach age 65, you will have saved $724,753. That's still a sizeable fund, but you had to contribute $160,000 just to get there - and it's no where near the $985,749 you could've had for paying much less.