How do you measure your success in life? For billionaire Bill Gates, an annual assessment of his personal and work life has been a tradition dating back to childhood. "Some people think it is corny, but I like it," the Microsoft co-founder said in a 2018 blog post.

Bill Gates admits that, at age 64, he assesses his life by different measures than he did in his twenties. Like most people, priorities change and values shift; things that mattered in our younger years don't matter as much in middle age and beyond.

"Back then, an end-of-year assessment would amount to just one question," writes Gates, reflecting back on his 25-year-old self's biggest goal: "Is Microsoft software making the personal-computing dream come true?" 

Millions of Microsoft users can say that it did, and now Gates has moved on to assess the quality of his life and work by the measure of fighting disease and reducing extreme poverty through the Bill and Melinda Gates Foundation.

The 1 meaningful question Bill Gates now asks:

But the questions to assess his life have also dramatically changed since his younger years at Microsoft. What he asks now, he says, "would have been laughable to me when I was 25," but is much more meaningful.

The question Gates asks now will make us pause and think about our own metrics of success, regardless of our professional accomplishments. He asks:

"Did I devote enough time to my family?"

Gates's priorities have shifted to more focus on family life and the special feeling of seeing his children excel. When asked, "Through it all, what makes you happy?" on Reddit earlier this year, the proud father of three beamed, "Some recently said that when your children are doing well it really is very special, and as a parent, I completely agree."

At the end of the year, if your family life has taken a backseat to your career priorities, the choice can be costly. Scientific analysis of the causes that lead to death in the workplace listed, among other things, "long hours/overtime" and "work-family conflict" as common sources of workplace stress destroying the health of U.S. workers.

For entrepreneurs and other professionals sacrificing work-life balance because of fear that the career will suffer, the solution is simple: Set clear boundaries around your family priorities first, and then use the same rigor to place strict boundaries at work. But it starts with the belief that family comes first and everything else will follow.

Having solid, non-negotiable lines around each area of life -- family and career -- will ultimately make you more focused, efficient, and effective at both.