Being born rich is arguably the easiest way to have wealth. If you want to build up millions of dollars yourself, you usually have to work hard. But can one really earn such wealth? How did multimillionaires do it? How did they get there?

These are the same questions Tom Corley asked himself when he began interviewing the super-rich for his Rich Habits study in 2004, reports CNBC. He was interested in the habits and characteristics of people who have built up a fortune. He spoke to 233 millionaires about their lives. On average, these individuals had assets of $3.2 million and earned an annual salary of $160,000. He recognized patterns - and worked out four ways to accumulate millions.

Around 22 percent of the people interviewed by Corley made their fortune this way. Corley adds that the savings route is not only the easiest route, but when started early, it is also the one with the highest chance of success. The saver millionaires made their first million in their mid to late 30s and by their mid-50s had an average net worth of $3.3 million.

Most in this group earned only a middle-class income, reports Corley. However, he admits that it was already in the six figures a year. And if not, these people lived very frugally. Low living costs run like a red thread through her life. Instead of high expenses, everything was saved. At least 20 percent and more of their monthly salary was put aside - and of course invested. The savings group has therefore invested the money prudently for many years. But Corley also knows that the saver-investor strategy isn't for everyone. "It requires tremendous financial discipline and long-term commitment," he writes on CNBC.

According to Corley, this is the most difficult way to gain wealth. Because to make a dream come true, you either have to start a business or become a successful actor or musician. Around 28 percent of the rich in his study belonged to this group and amassed an average net worth of $7.4 million over a 12-year period — significantly more than any other group.

What this rich group had in common was that they lived for their dream. They got down to work passionately and had a specific goal to which they subordinated everything else.

"But if you want to go down this path, you have to be willing to work long hours and deal with financial pressures. The dreamers in my study worked more than 61 hours a week before they finally achieved their dreams," says Corley. "There were almost no weekends or holidays." Some of his interviewees report that it was a difficult time, especially at the beginning. Some didn't buy a house or even canceled their retirement plans in order to put all their financial resources into the dream. A high risk - and therefore not suitable for everyone.

The climbers work in large corporations and concentrate on making a career as quickly as possible. According to Corley, this is the second most difficult way to become a millionaire. Around 31 percent of those surveyed managed it that way. On average, it took them 22 years to accumulate a fortune of $3.4 million. "In most cases, their wealth came from either stock packages or profit-sharing," Corley said.

The climbers have to adapt to long working hours, have to be excellent networkers and get used to having to travel a lot and also sacrifice a large part of their vacation for the job. However, there is one risk factor that is beyond your control, Corley said: "If your business is having financial difficulties, your time and investment may not be rewarded in the way you expected."

Approximately 19 percent of the study participants were able to follow the path of talent. They are among the best in their profession, receive high bonuses and are poached for a lot of money. The knowledge or skills of these people are outstanding. Some work in the medical field, others in the legal field. Sometimes a job with a large company is worthwhile, sometimes they are highly profitable small entrepreneurs.

Corley admits that very few people have these skills that have been put into their laps, but that this group of people has worked hard to develop their know-how. Expensive universities or schools, lots of time to learn and the best coaches - not everyone likes that. It also takes a lot of investment before the hard work pays off, says Corley.