There's a big difference between starting a company as a young entrepreneur with stars in your eyes and launching a business at an age when you need reading glasses. If you're a twentysomething student with an idea for a better search engine, like Google founders Larry Page and Sergey Brin, you can start over if the idea is a dud. If you're a retiree looking for a second career, you have a lot more to lose--including your life savings.

The upshot is that many people elect to hang up a new business shingle when friends their age are settling down to a life of leisure. The challenge is figuring out what to do and how to do it, without betting the farm on a venture that might not pan out.

Randy Nieukirk faced that challenge a few years ago. He had painted tractors for Caterpillar for 30 years, without getting much pleasure out of it, when he decided to take the company's optional "30 and out" retirement package at age 49. Soon after, he started a business framing houses for general contractors. Today he has plenty of work, several employees, job satisfaction and flexibility he didn't have when he was punching a clock.

Why was Nieukirk successful in building a post-retirement business and how can you accomplish the same feat? Here are some guidelines to steer you in the right direction.

1. Find the market gap in the business you know. Sometimes the best way to determine what business to go into is to identify a need that isn't being served by the business you came from. One of my friends used to be in the car wash business and knew that he sold three times more car wax than his competitors. After he retired, he set up a consulting company teaching his methods to other car washes. He knew there would be a demand, and he had the expertise to meet it.

2. Consider turning your hobby into a business. My father-in-law loved building computers, so after retirement he set up a small home computer building and repair business. An ex-banker in Savannah, Georgia, turned his love of local history into a tour business. You could do the same thing with gardening (be a consultant), baking (open a local cookie-making business) and so on. The added bonus is that if it's a hobby, it won't seem like work.

3. Investigate franchising. If you can find a home-based franchise that interests you, the cost will be relatively low, and you get pre-built systems and support materials so you don't have to reinvent the wheel. This also reduces the risk of failure, and you get startup training as well as ongoing assistance that you wouldn't get as a solo operator.

4. Use your connections. You've spent a lifetime building your network; now use it. I know a retired fruit and vegetable buyer who used to serve as a middleman between farmers and airline food services. Over the years, he developed contacts in Dubai. After retirement, he became a broker between the farmers and customers in the Persian Gulf. It was an ideal part-time business with no employees required.

5. Keep upfront expenses to a minimum. Nieukirk, the ex-Caterpillar painter turned home builder, didn't need an office and had to purchase nothing more than a van, some ladders and a number of tools. Starting small ensures that you can preserve most of your savings, avoid capital-raising efforts and associated debt, and back out gracefully if the business stumbles or the life of an entrepreneur doesn't suit you as well as you expected.

6. Avoid a 40-hour work week to start. Don't get yourself into a situation that requires your full-time attention from day one. You're not 20 years old anymore, and you might not have either the energy or the desire to work 40, 50 or 60 hours a week. Get your feet wet with a part-time commitment. You always have the option to add hours if business is good and you're having fun.

If you play your cards right, you'll find a way to be productive and make money even after your core earning years are behind you. You may not set the world on fire, but you'll put some extra money in the bank and enjoy yourself to boot.

Then again, as they say, a spark can start a fire. Colonel Harland Sanders was 62 when he sold his first Kentucky Fried Chicken franchise in 1952. By the time he sold his franchise operations in 1964, Kentucky Fried Chicken was a household name. So remember, you're never too old to be an entrepreneur.