Many people will have different perspectives in answering this question, so I will share mine, acknowledging that it represents merely my point of view and is not derived from any formal research, other than a lifetime of observation. To me, the three most important priorities in life are health, personal relationships, and economic independence.
Health
Without excellent health, a full, high-quality life is diminished by limitations that undermine productivity, and above all, the freedom to be active without constraints. To this end, it’s important for a person to use their intelligence to determine what daily practices stack the odds in favour of good health. For physical well-being, clean eating and regular exercise are vital, but excessively rigid adherence to a particular regimen can be counter productive. We need to have some pleasure in life and we should indulge our wants sometimes, but in moderation. Establishing healthy practices and routines requires a high degree of self-knowledge. When you know yourself, you know how to motivate yourself to work out when inertia prompts you to stay put; you know how to limit your food intake when your brain is calling out for another dopamine hit, and you know how to shut down your drinking when you already have a buzz. This self-knowledge that psychologists describe as “intrapersonal skill” is intellectual leverage to achieving excellent health.
Personal Relationships
The 17th century English poet, John Donne once asserted, “No man is an island.” Indeed, we are social animals and have evolved to need social contact with others for our psychological well-being. The dimension of intelligence required to maximize your chances of having rewarding social relationships is described by psychologists as “interpersonal skills,” in contrast to “intrapersonal skills.” This is the ability to achieve harmonious relationships with most people and deep loving relationships with family members. Those who have high interpersonal and intrapersonal skills (sometimes called “emotional IQ,” when grouped together) are more likely to have emotionally fulfilling lives. Leveraging your emotional IQ to establish a rewarding spousal relationship, deep family ties, and warm friendships is vital to a life of contentment.
Economic Independence
This is the dimension of intelligence where IQ or “the g factor” come into play. Educating yourself, whether through formal academic degrees or extensive reading and learning, is vital to achieving a proactive rather than a reactive mode in your daily life. If you have a reasonably high IQ you can use it to learn what you need to enter a profession, business or occupation for which you have a passion. As an old adage suggests: A person who loves what they do, never works a day in their life. People who enjoy their occupation can spend long hours at their work without looking at the clock. An additional, and perhaps even greater reward in achieving an education is that it expands your awareness of the world around you: past, present and future. By expanding your horizons, you not only become more interested in the many dimensions of life, but you also become a more interesting person.
If you use your higher than average IQ to allocate some of your time to study the magic of compound interest, the mechanisms of the stock market, investment instruments, and currency exchanges, you can build your personal wealth to the point where you will never have to work for money in your last few decades of life. Of course, for this to happen, you have to start as early as possible. Once you obtain this economic independence, you will never have concerns about money and your time is your own. With all this free time, loving relationships and good health, you can coast into that dark night in style. Of course, this is not a guarantee; you are merely stacking the odds in your favour. As Yogi Berra famously said, “Prediction is very difficult; especially about the future.”