From Mark Ford, editor, Creating Wealth: Jack and Jill live in the same apartment building and work in the same office. They both wake up at 7 a.m., shower, have breakfast, and get to work by 8 a.m. It is at this point that their habits diverge.

From 8 a.m. until 9 a.m. (when the rest of the workers come into the office), Jill plans her day and gets to work on a job that is important to her long-term goals.

Jack likes to get into work an hour earlier, too, but he prefers to spend the time “relaxing into his day” with a cup of coffee and the morning newspaper. Jack sees Jill working away and feels sorry for her.

“We both get credit for getting into work early,” he thinks, “but she has exchanged happiness for money.”

In his opinion, that makes Jill greedy, foolish, and, ultimately, self-centered.

David Niven, a college professor and author of the book The 100 Simple Secrets of Successful People, would half-agree.

“Yes, Jill is acting out of self-interest,” he’d say, “but so is Jack.”

Both of them choose to do what they do with their spare time because they believe they benefit from it. Jack doesn’t like work. Thus, he doesn’t want to work any more than he has to.

But since he has to work from 9 to 5, he figures he might as well do a good job during that time. And he does.

Jill does like to work. And although she doesn’t enjoy every single aspect of it, she especially enjoys the hour between 8 a.m. and 9 a.m. That’s when she plans her day, figures out what she can accomplish, and gets some work done on a project that she knows will change her life for the better.

By 9 o’clock, Jack feels relaxed, but just a little bit sad. In a few minutes, the office will be teeming with activity, his inbox will be overflowing with work, and the phone will be ringing off its stand.

Jill actually feels better than she did at 8 o’clock.

In their use of spare time, Jill is an investor, while Jack is a spender.

As an investor, Jill works from 8 a.m. to 9 a.m. because it gives her dividends. On a short-term basis, she is rewarded by knowing that her day is set, her inbox is organized, and she’s already done something she cares about.

On a medium-term basis, she benefits by enjoying a more orderly day. And on a long-term basis, the work she puts in now will provide her with all sorts of rewards in the future—higher pay, better work, more responsibility, etc.

As a spender, Jack is not willing to work that extra hour every morning. He would rather use it to “buy” some time that will give him instant gratification. Generally speaking, value compounds over time. This is true of money, of knowledge, and of work.

Invest $1,000 in the stock market today, and you can be pretty sure it will be worth about $2,000 in about eight years (assuming the stock market grows at its historic 9% rate). The same principle holds true with work.

Every hour that you put in today will be worth many times that amount later on. The rewards can be extraordinary if you think of them in terms of money.

Let’s say Jack and Jill are both earning $20,000 per year right now. By putting in an extra hour per day for a full year, Jill can expect to get salary increases that are, perhaps, 20% higher than Jack’s. If that’s the case, when he gets a $1,000 raise, hers would be $1,200.

That may not seem like much during the first year, but by the third year, Jill will have jumped up to a new level—a management position with a salary of $40,000.

If she continues to put in that extra hour per day, she will eventually be running the business, pulling down $175,000 per year. Meanwhile, though Jack has been enjoying his early morning hours, he will have had a very slow career arc. With any luck, he’ll be earning about $55,000 per year as a junior manager.

During the 20 years of their respective careers, Jill will have earned a lot more money and lived much better in terms of material goods. But Jack does not regret his choice.

After all, he figures that he has enjoyed an hour per day of pleasure—five hours per week, 260 hours per year, for 20 years—that Jill gave up. That’s 5,000 hours of “fun” that Jill didn’t have.

But now, Jack and Jill are 48, and Jill doesn’t have to work anymore. She was able to retire with $4 million in the bank. But Jack is forced to continue working.

With two kids in college, and a mortgage, and so on, he couldn’t retire even if he wanted to. Every 40-hour week that Jack now works is 40 hours that Jill can spend enjoying herself.

It will take Jill just 120 weeks, about 2 1/2 years, to catch up with Jack in terms of the amount of time he spent on personal pleasure all those years between the hours of 8 and 9 in the morning.

And Jill will not only be much richer and freer than Jack, she’ll also be able to continue enjoying herself… an extra 2,000 hours per year. That is how successful people use their spare time.