Like in Power of Focus 2: Limited Time, Part 3 speaks too about having another thing that is limited - our energy.
Everything that you take on, be it in the sense of thinking, being, doing - all and any activities that fall under this three categories, need energy. And we all personally have finite energy on a daily, and even hourly basis - that's why we have to sleep and rest, eat nutritious food, engage in spiritual and mental activities that refuel our energies for thinking, being and doing.
No one is exempt from it.
Anyone who tries to go without sleep, food, mental and spiritual activities, it will come to haunt you.
And all this leads to having a certain amount of finite energy that you must deliberately spend wisely, or waste it away. In an earlier article, it stated that we have a limited 9 years (time) of "our/us" time - if you don't have the energy to use these years well, or in these 9 years, you spend your energy pursuing things that don't matter in the mid to long run, what's the point?
Nowadays I spend more and more of my energy doing things that leads directly, or potentially will lead me towards the goals that I want to achieve, be it in fitness, business, spiritual matters.
For this, I spend roughly 4-6 days per week in the gym, roughly about 45-60 minutes each time; I spend about 2 hours a day thinking how to improve my business systems, operations and marketing; I spend more time praying between my tasks (okay, this one I can DEFINITELY do better); and these are my general priorities for the day.
And the night is when I spend time with my loved ones, sometimes talking, sometimes I destress by playing games - whatever calls. Or even cooking.
I know what I do in the day brings me closer towards my fitness, business and spiritual goals; whereas what I do in the evening strengthens my family and relational life.
As you have finite energy, knowing first what's important to you is the first vital step to take, followed by consistently doing what that leads you in the direction of your goals. Don't aim to overdo, but do what is enough and good.