NerdWallet recently published a fascinating study contending that high debt loads will prevent today’s college graduates from retiring before age 73. I have a few nitpicks with the study, but the underlying message is clear: millennials will have to be a lot smarter than previous generations if they want a decent, on-time retirement.

First, my nitpicks.  NerdWallet contends the current average retirement age is 61. It’s actual 62 for women and 64 for men, according to the most recent research by Alicia Munnell, director of the influential Center for Retirement Research at Boston College. (Munnell authored another interesting brief showing that the “real” Social Security retirement age is now 70, which gives people the same expected length of retirement they had back in 1940. Furthermore, an argument could be made to move it to 73 for millennials, who will live even longer than Boomers. I won’t make that argument, though, since I wouldn’t have to wait that long…I’m sure most others wouldn’t, either.)

The NerdWallet study also assumes that paying off student loans inevitably will prevent millennials from making significant contributions to their retirement funds for the first 10 years of their careers—years when they would get the most benefit from retirement contributions. Thanks to the miracle of compounding, $1,000 contributed to a retirement account can grow to $20,000 or more by retirement age. Wait 10 years to contribute that first $1,000, and your growth is cut by half, to $10,000.

So here’s what millennials should know:

Retirement contributions can’t wait. Retirement really has to be your top priority from the time you get your first paycheck. You can’t get back lost opportunities to save and nothing—including debt repayment—is more important than this.

Don’t be in a rush to pay back student loans. Federal student loans, especially, are flexible debt with a ton of consumer protections. If you can’t pay your student loans and contribute to a retirement fund, then consolidate your loans to a longer payback period so that you can put some money away for tomorrow. Yes, you’ll pay more interest on your loans, but that cost will be swamped by the growth of your retirement accounts once you factor in the tax breaks and compounding you’ll get. If you have a company match, the calculation’s even more of a slam dunk.

Get a better 401(k). Beggars can’t be choosers, and many millennials will have to take what they can get in this very tough job market. As they build their skills and networks, though, they should start looking for positions with companies that offer good 401(k)s with generous matches. In the meantime, they should contribute to any workplace plan that’s offered. No plan? Set up an IRA with automatic transfers to fund it. You’ve got to find a way to save if you want to quit work someday.