That's tough, considering that most Americans neither know nor correctly estimate how much money they might need to keep the wolf from the door during retirement — or even to retire at all.

Here's a look at 9 reasons why retirement as we know it today might be a terminal case — unless things change drastically, and soon.

9. Ignorance

Most Americans have no idea how much they might need to retire, which leaves them behind the eight ball when trying to figure out when or whether they can afford to do so.

Of course, it's hardly surprising, considering how many are members of the “sandwich generation,” who find themselves caring for elderly parents while at the same time raising kids, or even trying to put those kids through college.

With soaring medical costs on one end and soaring student debt on the other, not to mention parents supporting adult children who have come home to roost, it's hard to figure out how much they'll need to meet all their obligations, much less try to save some of an already-stretched income to cover retirement savings as well.

8. Poor calculations

We already know most workers don't know how much they'll need in retirement — but it's not just a matter of ignorance. They don't know how to figure it out, either.

More than half — 56% — figure they'll be able to get by during retirement on a million dollars or less, while 9 percent overall think up to $100,000 will see them through.

And 19% just flat-out say they don't know how much they'll need.

Considering that health care costs alone can cost them a quarter of a mil during retirement, the optimists who think they can get by on $100,000 or less and even those who figure $100,000–$500,000 will do the job are way too optimistic — particularly since saving for medical costs isn't one of their top priorities.

7. Despair

It's pretty hard to get motivated about something if you think it's not achievable — and that discourages a lot of people from saving for retirement.

Those who have a “magic number” that they think will see them through retirement aren't all that optimistic about being able to achieve that level of savings, with 40% of nonretired workers saying that reaching their magic number by retirement will either be “difficult” or “virtually unattainable.

6. Luck

When you don't believe you can do it on your own, what else is left? Sheer dumb luck, to quote Professor Minerva McGonagall at Hogwarts after Harry and Ron defeated the troll.

Only instead of magic wands, 17% of would-be retirees are sadly (and amazingly) counting on winning the lottery to get them to their goal.

5. The gig economy

Retirement? What retirement? Millennials in particular think they'll need side jobs in the gig economy to keep them from the cat food brigade.

In addition, exactly half of younger millennials aged 18–24 believe they need to take on a side job to reach their retirement goals, compared with only 25% of all respondents. They don't believe that just one job will cut it any more.

4. Attitude adjustment

While 83% of current retirees are not currently working or never have during their golden years, the majority (83%) of millennials plan to work in retirement — whether for income, to keep busy or to pursue a passion.

The rise of the “gig economy” has created an environment where temporary positions and short-term projects are more prevalent and employee benefits such as retirement plans are less certain. This may be why more millennials (15%) are likely to rank an employer's retirement plan as the most important factor when taking a new job compared with GenXers (5%) and baby boomers (5%).

Older generations had unions to negotiate benefits for them. Millennials might realize they have to do it all themselves, but they aren't negotiating for salaries high enough to allow them to save.

And union benefits or not, 64% of boomers, 79% of Gen Xers and even 17% of currently retired workers plan to work in retirement.

3. A failure to communicate

Lack of communications is probably not surprising, since most people won't talk about savings anyway.

Fifty-four percent of respondents say that the only person they feel comfortable discussing their current retirement savings with is their spouse or partner. Only 36 percent would discuss the subject with family, and only 22% would talk with friends about it.

And as for coworkers? Just 6% would talk about retirement savings with colleagues — although more communication on the topic no doubt could provide quite an education on both sides of the discussion.

2. Misplaced confidence

They won't talk about it, but they think they do better than others at saving for retirement. How might that be, when they don't know what others are doing about retirement?

Forty-three percent of workers say they are better at saving than their friends, while 28% believe they're doing better at it than coworkers; 27% think they're doing better than their spouse or partner, 27% say they're doing better than their parents and 24% say they're beating out their siblings.

All without talking about it.

1. DIY

They're struggling to figure out how much they need, many won't talk about retirement savings even with those closest to them and they're anticipating working into retirement — but millennials in particular are taking a more hands-on approach to their investments.

Doing it oneself could actually be a good thing, since it could mean the 70% of millennials, 72% of GenXers and 57% of boomers who are taking the reins into their own hands better understand what they're investing in and how they need to structure their portfolios.

However, doing it oneself without sufficient understanding — and millennials in particular are also most likely to describe their investment personality as “DIY,” with 32% making their own rules when it comes to investments, compared to 19% of all respondents — can be a problem.

After all, as the saying goes, “A little knowledge is a dangerous thing.”