Andy Grove, in his book High Output Management, wrote:
“A manager’s work is never done. There is always more to be done, more that should be done, always more than can be done.”
On the surface, this sounds almost impossible. Surely, at some point in time, one should be able to finish a task. But the longer I have been a manager, the more I have realized that Grove is right.
As a leader, you never really finish your work. You stop because the day ends, or because you no longer have the capacity to carry out the next task. You rarely reach that satisfying moment where everything is clean and “done.” Some days are busier than others, but the queue is never truly empty.
That creates a different question.
If the work is never going to be finished, what determines how much of it we can do well?
In 2023, I wrote about getting work done as a manager. The ideas were practical and helped me organize my workload, but they weren’t enough to sustain clarity and productivity throughout the day. On most evenings, I still arrived home completely drained. I had been thinking about productivity primarily as a time problem.
But time wasn’t the only thing running out. I started noticing something else: my ability to do good quality work changed significantly throughout the day.
This begs a question:
Why do we feel significantly sharper at the beginning of the day than at the end?
Why does context-switching for a few hours leave us so completely drained?
Why do hard conversations or continuous batches of meetings often leave us feeling emotionally bankrupt?
I began paying closer attention to the quality of my output when exhausted. I would write something in the evening, feel reasonably satisfied with it, and then read it again the next morning. I would immediately catch obvious mistakes. The text failed to capture my thoughts with the depth and clarity I had intended.
When we think about productivity, the obvious measure is time: How much can someone accomplish between 9 AM and 5:00 PM? But time is not a sufficient measure of performance or productivity.
Two hours when you are sharp are not necessarily equivalent to two hours when you are exhausted, and you cannot measure productivity by how many difficult conversations or context switches you can cram into a single hour. If you had 10 conversations and they lack depth and clarity, they might not have the intended impact you want. “Done” doesn’t equate to impact.
There is another finite resource that is just as important as your time: Energy.
Going back to my Physics class days, my teacher defined energy as the capacity to do work. That definition has stayed with me because it remains true outside of Physics. You may have the time to do something, but if you lack the energy, you lack the capacity to do it well—to the level of quality and satisfaction you might expect.
Time determines how long you have to work. Energy determines how well (productively) you can be when you do that work. And energy has dimensions.
Different Work Burns Different Energy
Growing up, I often worked alongside my father on his farm. We would go to the farm at 7:00 AM as the sun rose, working until 11:00 AM with occasional hydration breaks. Then we would take an hour to eat brunch, rest, and recover before working until 2:00 PM. Toward the end of the day—especially early in the farming season—I often find myself exhausted. As a teenager, that was only the exhaustion I knew. Exhaustion that comes from physical energy.
Years later, as a software engineer, I would face complex technical problems under tight deadlines. After hours of continuous problem-solving, I would notice my thinking slowed down. Ideas that often come effortlessly in the morning rarely come in the evening. I would reread the same paragraph four times without absorbing a single word; my brain refused to process things clearly. Yet, after stepping away for a good night’s sleep, the same problem often felt effortless the next day. As a knowledge worker, I learned a new form of exhaustion that isn’t physical but rather cognitive or mental.
When I moved into management, I was no longer writing code all day. Instead, I was context-switching rapidly across disparate domains: hiring interviews, performance reviews, roadmap planning, stakeholder alignment, and endless meetings. By the end of the day, I would feel a deep mixture of cognitive fatigue and emotional depletion. I would notice myself struggling to concentrate in late meetings, forgetting simple details, or feeling my brain actively shut down.
All three experiences revealed the same underlying truth: I was drawing from a finite reserve of energy. Once it was depleted, my performance degraded until I had a chance to recover.
Often we focus on maximizing time: how much we could get done within the finite time resource we have; after all, everyone gets 24 hours a day: no more and no less. We think about whether we could do more within those hours. Other times, we could increase the number of hours we work per day to get more done. The truth is, as we manage time, there is another resource that’s crucial to getting things done that gets depleted with use unless renewed.
Think of your phone battery. The battery gets depleted when used and renewed on charge. If you’re running your flashlight, streaming 4K video, and making a call simultaneously, your battery will drain faster than replying to an email. But there are certain things we can do to optimize battery use before it needs renewal. This is why phone manufacturers, including Apple, offer guidance for maximizing battery performance.
How does this apply to tech leadership?
Most people (like me) transitioned to leadership roles after years of working as individual contributors. As an IC, you spent years refining your time management skills. You learned how to break work into smaller pieces, estimate effort, and shorten feedback loops. You guard your calendar fiercely to protect deep focus time—and your manager might even help to enforce those boundaries.
When an IC transitions into management, the nature of work changes. It is common to feel overwhelmed, as though work is suddenly happening to you rather than by you. Suddenly, your calendar is filled to the brim amidst countless interruptions. Work no longer arrives in a predictable sequence. Instead, it comes from every direction, demanding constant context switching.
When this happens, the instinct is to apply the same time management strategies that worked well while an IC. Some might optimize their calendar, squeeze in more meetings, work longer hours, and try to become more efficient. These are all good, but you have to realize that there is another optimization you can do beyond squeezing so much out of the limited time.
One of the mindset shifts in stepping into tech leadership is recognizing that time is not the only limiting resource. Energy is another currency you spend, and you draw on different kinds of energy, often without realizing it.
When you understand different forms of energy, you’ll start to recognize why some days leave you exhausted even though you barely left your chair. And why some other days, you want to shut off and never see a person or speak to someone again.
Your ability to think clearly, make sound decisions, stay emotionally present, and lead will depend just as much on how well you manage your energy as how well you manage your time.
What are different types of Energy?
Tony Schwartz and Catherine McCarthy wrote about the main types of energy in their book, whose management is vital for performance.
Physical Energy: Physical energy is your body’s capacity to sustain work. We experience physical fatigue when our body systems reach their limit through energy depletion, prolonged exertion, hunger or nutrition deficits, or inadequate rest.
While technical leadership is less physically demanding than manual labor or construction work, your body still influences your performance. Poor sleep, skipping meals, or consuming excessive meals can make you fall out of a chair. You can’t easily be present and lead the way you’re supposed to if your body is failing or running on 4 hours of sleep.
Mental Energy: Mental energy is a function of your ability to sustain cognitive tasks such as concentration, information analysis, decision-making, and problem solving. When you experience mental fatigue, you feel cognitive tiredness, your judgment deteriorates, and you might overlook important details.
You might scan a piece of text 3 times and still fail to understand what it is about. If you’re reviewing a design doc when your mental energy is depleted, your value add will decrease.
Emotional Energy: Emotional energy is your ability to feel, react, and process daily ups and downs. It’s one’s physiological capacity to manage and regulate their emotions. A manager may absorb emotions throughout the day. From directly expressing their frustration to managing or working with difficult stakeholders, you may leave each conversation feeling composed, but every interaction requires emotional effort. Some conversations are depleting, and others could recharge your emotional energy. You won’t be able to control which conversations you have, but you can control how you react and show up.
Spiritual Energy: Comes from having a sense of purpose and acting consistently with your values.
These forms of energy are interconnected. A poor night’s sleep can reduce your mental sharpness. Mental fatigue can make you emotionally reactive, and not deriving purpose from one’s work can make the work draining.
How do you manage them?
Knowing the different forms of energy is only useful if it changes how one works. The usefulness comes from spending your energy on the work that benefits most from it.
Think of your energy as a budget that can be replenished under certain conditions. You have a limited amount of energy available at any given time. Meetings, decisions, difficult conversations, and context switches withdraw from that budget. If you overdraw the budget in the morning without some time to replenish, you won’t have enough left for the work that might need it most in the afternoon.
Suppose your day looks like this:
9:00 AM – Weekly roadmap review
10:00 AM – Deliver performance feedback to a struggling direct
11:00 AM – Interview a candidate for a Staff Engineering role
12:00 PM – Launch
1:00 PM – Review a design document
2:00 PM – Write the Q4 strategy document
3:00 PM – Stakeholder update and experiment results review
4:00 PM – Catch up on email and Slack
This looks like a normal calendar. But when viewed through the lens of energy, you might notice that not every activity draws on the same type or amount of energy.
Reviewing a design document and writing a Q4 strategy document require mental energy. The performance feedback conversation requires emotional energy: patience, empathy, and the ability to listen, communicate, and coach effectively. Interviewing a candidate requires both. You need mental energy to evaluate their competence while also using emotional energy to create a positive candidate experience.
During an urgent hiring period, especially for roles I’m trying to close quickly, I have found that when I jump straight out of 1 hr interview into a high-emotional-energy conversation, I often struggle to be fully present.
When you understand your energy—what depletes it and which tasks require which types of energy—you can structure your day differently.
You might schedule the Q4 strategy work for the time when you’re mentally freshest. You might protect some time before a difficult one-on-one so you can decompress and be fully present. If you’ve just spent an hour in an emotionally demanding conversation, you might find it difficult to create the best hiring and candidate experience if you immediately jump into an interview. Taking a short walk or having some quiet time before the next meeting might help you recover some of that energy.
About a year ago, I was responsible for three large, concurrent projects across three pods. My blast radius had expanded dramatically, as had the number of people I needed to sync with every day.
For the first time in my career, I felt stretched to my absolute limit. No amount of ruthless time prioritization could save me.
So I changed my system to match my energy.
I protected my mornings for deep mental work, when my energy and focus were at their highest. I batched emotionally demanding conversations into dedicated days rather than spreading them throughout the week. I pushed administrative tasks—the work that required less mental and emotional energy—to the end of the day.
This simple change made the workload manageable and worked far better than what I had been doing before.
To me, that is the missing piece in time management. Time is finite, but so is energy. You can control your calendar down to the minute and still be ineffective if you spend your best energy on work that doesn’t deserve it.
Ultimately, managing your time and prioritizing your work are only part of the equation—it’s equally important to manage your energy. Safeguard it, invest it intentionally, and dedicate your peak energy to your most important tasks.
A leader's exhaustion is never private; it radiates. This exhaustion often creates a butterfly effect such as delayed decisions at the top that trigger panic. The ultimate cost of a depleted leader is the price everyone around them pays.
Earlier today a developer we work for called one of our employees and was rude and accusatory. Later we found out the developer just realized that his primary manager just announced 2 weeks paid time off without notice immediately leaving the developer with twice the work.