Open any magazine aimed at the upper middle class and you’ll find lots of ads about retirement planning: financial firms fighting over which one will ‘advise’ you and get you to invest your money with them.

But, for most people, that isn’t the most important part of retirement planning. In fact, most people don’t have significant retirement savings, so arguing about who or how to invest them is irrelevant. Their “financial planning” is more likely to be about whether and when to pay the credit card bill.

So what kind of retirement planning really matters? There are lots of answers, but here are two of the most important: How long you work and when you apply for Social Security. For most people, these matter far more than whether your savings are invested in stocks or bonds.

Working Longer Requires More than Wishful Thinking. One of the great blessings of modern medicine is that people are living longer. But one of the consequences of that blessing is that unless people work longer and/or save more while they’re working, they’re more likely to run out of money in retirement than ever before. (The decline of traditional pensions, which paid lifetime income benefits, hasn’t helped either.) Most folks know this and are responding. According to a recent survey, 65 percent of baby boomers expect to work past 65.

But those expectations may not be met. Currently, about half of workers stop working before age 65: some are wealthy enough; more often they’re just not healthy enough.

Flexible retirement is more slogan than fact.  Moreover, the job market isn’t as flexible as some may hope. Yes, an increasing percentage of seniors are working at least occasionally (~35 percent of men over 60, ~25 percent of women), but that doesn’t mean they’re doing their dream job on their chosen schedule. Increasingly, most of those who do work past 65 work full-time. Twenty years ago, about 60 percent of workers over the age of 65 worked part-time; today about 60 percent work full-time.

It’s not clear why part-time work has declined, but one reason may be that employers still haven’t adjusted to the idea. A recent Transamerica Survey found that 66 percent of age 55+ US workers expect they will enter retirement flexibly — but only 25 percent report that their employer offers the opportunity to move from full-time to part-time. However, the best way for employers to change is for their employees to ask (or have a union that does).

Retirement planning involves more than wishful thinking. If you want a flexible or a phased retirement, you need to know what your options really are – and the time to find out is long before you’re on the verge of retirement.

Defer Applying for Social Security?  The other step that matters for most people is when they choose to apply for Social Security. Many apply as soon as they legally can do so, generally at age 62. For most people, that’s a mistake, because it means they will get reduced payments for the rest of their lives. Most others claim their Social Security benefits by the time they reach the “normal retirement age”, which for baby boomers is 66 years. (The normal retirement age is gradually being raised; for those born after 1959 it’s age 67.) For many people, that’s a mistake, too, because your lifetime benefit increases each year that you delay from 62 up to age 70.

How much more will your Social Security be if you start taking it at 70 instead of claiming benefits at the earliest possible age? A lot. For baby boomers, waiting till 70 increases the annual benefit by about 8% or each year of delay. That means instead of taking an annual payment at 62 of $10,000 a year, waiting 8 years means your annual payment will rise to $17,600 – inflation indexed for life. (If you keep working after age 62, then the math can be even more compelling, because Social Security is based on your highest 35 years of earnings.) If you are married, delaying also increases payments to your spouse after you die.

Of course, lots of folks have justifications for taking the lower payment at 62. Some say, “I won’t live long enough to make up the difference” – but in fact most people do live that long and many live longer. Others say, “I need the money to pay my bills.” But if you have savings or home equity, it’s worth using those first and taking Social Security later.

So the next time someone approaches you about moving your 401k money over to them, consider the option they won’t tell you about: spending it first and deferring Social Security. After all, Social Security gives you a guaranteed 8% return for waiting – and an 8% guaranteed return is hard to beat. (But they probably won’t tell you that, either.)