A few years ago, I started asking myself the same question at least once every day: “Am I focused on the right priorities?” Life as a founder can be hectic, and I don’t want the daily execution to overshadow the truly important things I want to achieve. So I check in with myself at the end of the day, to make sure I’m spending enough time on those high-priority items.

I encourage everyone at Guardant to do the same thing, and we take a similar approach as a senior management team. We have a three-year plan, an annual plan and specific areas of focus that we revise at least once per quarter. But we also do a review every week to track progress toward our long-term goals and initiatives and make sure we’re actively moving them forward.

You often hear that you should solve a problem you’re passionate about, or one that will affect a lot of people. I think you should do both. It’s important to pursue a passion—but you should think carefully about which passion you choose. If you focus on an unsolved problem at the global level, you can have a much larger impact.

For me, it’s serving cancer patients. If we can develop a blood test for early diagnosis, that will affect millions of lives. And even if we don’t reach every one of our goals, I can still be satisfied knowing that I did my best to make a dent in a big problem, and I’ll look back knowing I spent my time on something I cared about.

I started doing daily check-ins with myself personally as well as professionally. I actually score myself at the end of every day. I have a little notebook where I write down the things I want to do daily, like read and exercise and help others, and before I go to bed at night I go through the list. It’s nothing innovative—lots of people journal or make to-do lists—but the daily practice makes it harder to skip things. It forces me to invest in my own training and continuing education.

It’s also made me more self-aware, because I’m actively taking stock of what I accomplished that day, or what I didn’t accomplish and why. It’s been a gradual process, but I can see a clear difference compared to a few years ago, both in terms of achieving specific goals I set for myself and in my overall time management. I’m more proactive, instead of reactive, and I’ve seen a huge impact on my focus and productivity. It’s a really good return on investment from such a simple exercise.

Something I’m always learning, and wish I’d started to work on earlier, is the importance of being an inspirational leader. When we started Guardant, I don’t think I realized how critical that is. Your natural inclination in those early days is to focus on execution, but starting a company is about more than just having an idea and shipping a product. You need a team that’s genuinely fired up, especially when you’re scaling quickly. If you can translate your own passion into inspiration for the team, that will make the company much more productive when things are going well—and help you get through the tough times, too.

It’s easy as a founder to push that kind of self-development work aside when so many other things are vying for your attention. But there’s always room to learn, and if you don’t put real energy into improving yourself, your company can easily outgrow you. If you want to be ready for the next chapter, you have to not only be open to feedback, but also committed to self-training.

I always have two books next to my bed—one on personal development and one on business. The personal one I’m reading now is Words of Truth, by Ostad Elahi. He’s my favorite philosopher in Iran, which is where I’m from. The book is essentially about being a kinder, wiser person and a good servant to the world around you—the idea that whatever you want for yourself, you should want for your community. It’s a simple message, but it’s had a deep impact on me. And it’s not something you have to go off in a cave to practice. It applies to modern life. I can follow the principles even when I’m working 90 hours a week, in the way I serve our team and the people we help.

The other book I’m reading right now is The Score Takes Care of Itself, which is by Bill Walsh, the former 49ers coach. It’s about his leadership philosophy and the culture he built. When he took over in 1979, the team had had multiple losing seasons, and within five years they’d won two Super Bowls. There’s a lot of great insight in the book about making sure you recognize people when they do well and getting ready for all possible outcomes, but the most important takeaway for me was that the culture you create depends on the example you set as a leader.

I make lots of mistakes. One recent example was a month or two ago, in one of Guardant’s portfolio meetings. We were discussing a program we’d been working on for six months, and I decided we should pause it. But one of the members of the senior management team wasn’t in that meeting, and when he and I talked about it afterward, he presented evidence that showed I’d made the wrong call. We had a day or two of back-and-forth, but in the next portfolio meeting I told the team I’d made a mistake, and we kept the program going.

One of our core values at Guardant is intellectual humility, so my actions as a leader have to reflect that. When I realize I’ve been wrong, whether I change my mind based on a new experience or a new piece of information or because I simply made a mistake, it’s critical that I acknowledge that—not just to myself, but to the team. That’s the norm I want us to have as a company, so I need to set the example.

For me, I think it’s days and weeks. I do daily check-ins, and I sometimes look back on a weekly basis, too, to see if any course corrections are needed. Time is one of our biggest assets, and we only have so many weeks left in our lives. I can’t afford to let weeks pass by without making the progress I intended to. I think that’s also true for Guardant as a company. We move quickly and don’t have the luxury of addressing our overall direction only once per year or even once per quarter.

That said, I think you need bifocal vision in terms of time, because the danger of thinking only in terms of days and weeks is that you lose sight of the long-term goals. You have to know where you’re heading over the next year or three years, but then look down at the days and weeks in front of you to keep focused and moving forward on a successful path.