T o secure the future you dream of in retirement, you’ll have to avoid some deadly but all too common planning mistakes. Pay careful attention to the following...

Mistake: Procrastinating. Don’t delay in starting the process of planning for retirement.

Often people in their 50s decide they want to retire at 60. But they find they made that decision too late to achieve their target retirement date.

Planning for retirement ideally should start when you get your first full-time job. Very few people, though, even think about retirement while still in their 20s.

Reality: At least 10 years is a realistic time frame to put your financial and personal life in order before your actual retirement date. Generally, the more time you give yourself, the better.

Mistake: Not understanding how much income you’ll need in retirement. The key to a secure retirement is making sure your money lasts as long as you do.

A rule of thumb in projecting income needs in retirement is that you’ll need at least 75% of your current income. But many factors can bump this figure much higher...

You could live a very long life. Usually, retirement income needs are based on a person’s life expectancy. According to actuarial projections, people who live to age 65 can expect to live another 12 years.

But the number of persons at least 100 years old is growing impressively, and you could be one of those who lives beyond the century mark. You’d certainly want your income to see you through.

You may need to provide financial assistance to others. Adult children... your siblings and/or parents may turn to you for help. You may have planned for your own retirement income needs but not considered the potential needs of others.

You want to live better than you do now. The decision to travel a lot or buy a second home could boost your income needs in retirement over what they currently are.

Retirement community/assisted living. When you can no longer live on your own but don’t require nursing home care, you may need to consider an assisted-living housing arrangement that not only provides you with living quarters, but also meals, housekeeping services, laundry, recreation and some on-site medical assistance.

Depending on where you live, assisted living costs on average $3,000 a month. Expect to see prices rise as baby boomers reach their 70s and 80s -- starting in about 2016.

Mistake: Counting on Social Security. You may have paid into the Social Security system for 30 years or more. While the system may be fiscally sound -- for now -- don’t expect benefits to be substantial. At best, Social Security benefits only provide a safety net to retirement income. (Currently, the most you can expect is about $1,500 a month.) If you want to retire early -- before the normal retirement age fixed by law -- your benefits are permanently reduced.

Example: In the past, when the normal retirement age was 65, those retiring at 62 received a benefit reduced by 20%. Today, normal retirement age for someone born in 1938 is 65 years and two months (it is scheduled to rise to 67 years).

If this person retires in 2000 at age 62, benefits are reduced by 20.83%. For those with a 67-year retirement age (starting in 2022), benefits will be reduced by 30% for those opting to take benefits starting at 62.

To get some idea of what to expect from Social Security when you plan to retire, you can use a benefits calculator on the Social Security Administration’s Web site at www.ssa.gov/retire/calculators.htm.

Mistake: Underestimating medical costs. Many believe that Medicare, a federal benefits program covering many types of medical expenses starting at age 65, will cover everything. Medicare only covers certain medical expenses. And you must pay deductibles and co-payments on these expenses, plus the expenses Medicare does not cover, out of your own pocket.

Alternative: You can deal with uncovered expenses by carrying supplemental health insurance coverage (a “Medigap” policy -- costs vary according to the coverage you select).

Mistake: Failing to buy long-term-care insurance early. Generally, Medicare doesn’t cover the cost of long-term care that may be required by those with chronic diseases, such as Alzheimer’s disease, or simply old-age-related incapacity.

The cost of long-term care is steep, today averaging about $50,000 annually nationwide and topping $100,000 in some locations. Only a few can afford to pay for this kind of expense out of pocket.

Those with income and assets below modest governmentally fixed levels can qualify for Medicaid to cover nursing home costs. But anyone with assets to protect won’t qualify and needs to carry private long-term-care insurance.

The younger you are when you take out the policy, the lower your annual premiums. You’ll also avoid being denied coverage due to preexisting conditions.

It’s generally advisable to start this coverage in your mid-50s. Good news: An increasing number of employers are offering this type of coverage.

Mistake: Thinking you can retire early. Meteoric rises in the stock market in recent years may lead you to believe that you now have enough money to retire on. Think again. These days, stock and stock option values change fast. Review your finances carefully before you decide to quit your job.

Mistake: Believing retirement will be nirvana. Financial concerns are only one aspect of retirement. Many who retire early get bored and go back to work within a year or two, either on a voluntary or paid basis. Decide how you’re going to spend your time before you decide to retire.

Mistake: Failing to seek expert guidance. You may think retirement planning is a do-it-yourself process. But even if you’re adept at handling your own investments, it is a good idea to review your plans with an expert, particularly a certified financial planner (CFP), who has plenty of experience helping people make the transition from work to retirement. This expert may bring up areas of concern you have overlooked and help you address them.

Retirement income planning isn’t a one-time process: You need to review your plans regularly and make adjustments as things change.

Example: If inflation should run above the historic levels of 3% to 4%, you’ll need to make changes in your income projections.