This story is part of the Behind the Desk series, where CNBC Make It gets personal with successful business executives to find out everything from how they got to where they are to what makes them get out of bed in the morning to their daily routines.
David Selinger's LinkedIn bio reads like an endless roll call of tech start-ups spanning the past 25 years.
Some, like online real estate company Redfin, have been extremely successful. Others have long since shuttered. In total, the 42-year-old Selinger — an early Amazon employee, co-founder and CTO of Redfin and most recently, founder and CEO of home security start-up Deep Sentinel — has been a co-founder, early employee or an advisor at no fewer than 19 Silicon Valley start-ups.
Selinger tells CNBC Make It that he is the type of person who always needs to be working on something. He says he "tried to retire" after stepping down as CEO of e-commerce software company RichRelevence in 2015, "and within a week, I was staying up till 3 o'clock in the morning writing code."
A year later, Selinger launched Pleasanton, California-based Deep Sentinel, which uses artificial intelligence to power smart cameras for its home security systems. The company has raised more than $25 million from investors, including Amazon founder Jeff Bezos, according to Selinger — who says he's already eyeing bigger fish.
"I can see Deep Sentinel being a public, $50 or $100 billion dollar company in 10 years, [and] that's what I'm focused on every day," he says.
Selinger's origin story is nearly stereotypical. In 1997, he dropped out of Stanford University for a software engineer job at a tech start-up called FlyCast. When it got acquired a couple years later, Selinger parlayed his experience into a job at 2Roam, another tech start-up — where, "including some moonlighting," he made $100,000 per year.
2Roam went under in 2001, and that's where Selinger's story deviates from the norm — because unlike many other Silicon Valley stalwarts, he returned to school and finished his degree in 2003. Since then, his career has taken him from researching customer behavior for the development of Amazon's product recommendation system to building the interactive real estate maps and data analytics software that helped Redfin reach its current $5.2 billion valuation.
Here, Selinger talks to CNBC Make It about why he opted for a career in tech, why he loved going back to college after dropping out, and some of the lessons from his long string of start-ups, including what he learned working with Bezos at Amazon.
On getting a job at Amazon in 2003 and working with Jeff Bezos: 'I was probably more egotistical than I needed to be'
It was a cool job. I was probably more egotistical than I needed to be, and that was actually really good, because I wasn't nervous when I met [Bezos the first time]. It was like, "I'm just having a meeting with Jeff and the entire executive staff."
That set me up to not be intimidated by that experience. He was an intimidating person, even back then, though. He was precise, definitive and wicked intelligent.
My team presented [an early model for collecting customer behavior data] my very first day, and his answer was, "This is horrible. And we need to meet every single week until this is fixed." I think that really set the table. I want to say [those meetings lasted for] three months.
We would show up and we'd say, "Well, here are our new graphs." And he was like, "I didn't hire you guys to make graphs, I hired you to make money. Where's the money? The only way you make money is if you're writing software."
We started delivering that code. We delivered a project plan. And then things started getting a lot less stressful. He was still very precise about what he wanted to come out of it, but it was a lot more comfortable.
On falling in love with technology at a young age: 'I was the quintessential geek'
My mom bought a PC when I was 6 years old — which, to kids these days, seems like a stupid introduction. You have to imagine that [in the early 1980s] most people did not have any sort of computing device in their home.
I fell in love. I taught myself to program in BASIC when I was 6. By the time I was 9, I knew about four [programming] languages. And by the time I went to Stanford, I knew more than 20 programming languages.
I didn't make any friends in high school or elementary school because I'd already made up my mind: I was the quintessential geek, and just loved technology. There was nothing more enthralling to me than figuring out how to create in a world where nobody else knew how to create.
On the non-negotiable aspects of his daily routine: 'I am super anal-retentive'
I wake up in the morning, and I have the same breakfast every single day, so I don't have to worry about it. I have a Bulletproof coffee, and I heat up six slices of kielbasa sausage. I stretch for about three to five minutes every single day. My chiropractors advise me on which ones to do.
I am super anal-retentive. I spent five years experimenting with other notepads until I found this one. [Selinger holds up a $15 notebook made by Miquelrius, a Spanish brand he says he's been using exclusively for the past decade.]
I have a stack of them. They're the exact same size. They're all graph paper. They are white paper, not recycled paper. I write my To Do list every couple of days. I move items from my last To Do List over to [the new] one. And if I have to move it twice, then I know that it's either deprioritized, or there's a problem.
Writing it every time forces [me] to review: Is it important? Am I ever going to get to it? Or, can I delegate it? Those three things: boom, boom, boom. That cycle helps me stay focused on the things that are meaningful.
On the one word his assistant would use to describe him: 'Intense'
"Intense," in every single possible sense [of the word]. If you did references, that would be the first word that everybody says [about me]. And, then they would either say they love me or hate me. Absolutely consistently.
On his most important leadership lesson: 'Don't lie'
No. 1: Don't lie. We tell all kinds of white lies just to make things a little easier. But then you have to keep track of what you told everyone, and that's just a f---ing bummer, man.
That plays out in business as well. The term "radical transparency" [where leaders share every aspect of their company's performance data with their employees] has gotten a lot of inertia behind it recently.
I have our CFO [at Deep Sentinel], every single week in front of the whole company, tell everyone how much money we have in the bank. When you're on the ups, it's really easy to do. But when you're on the downs, it's like, "I want to hide that, right?"
Every start-up goes through a stage where you may go out of business. But let me tell you something: When you're about to go out of business — even if you don't, but if you're headed there, and it's getting close — everybody [in the company] knows. There's the big secret, right? Everybody can tell, behaviors change, things are a little creepy.
The other thing, though, that everybody doesn't realize: Most people think it's worse than it actually is. So, by being transparent, at least everybody knows, and they know exactly how bad it is.
On dropping out of Stanford during the dot-com boom, and then going back to school: 'It was magic'
For anyone who's thinking, "Should I stop out, and then come back to school later?" I have two answers for you. One, if you're really serious about it and you have a great path, really consider it. And then, two, when you do that, really commit yourself to coming back.
By the time I came back, I had figured out one of life's most important lessons, which is how to manage your time. One of the things I heard from students all the time was, "Oh, I'm so busy! This class is so hard!" [But] I recognized, "Oh my god. In the real world, where I spent the last three years, there are exactly zero Nobel laureates that will let you come and talk to them at 2 p.m. on a Tuesday." At Stanford, there are 20 Nobel laureates that all have office hours, and most people don't go to them because they're "so busy!"
It was magic. It was one of the best periods of my life.
This interview has been edited for length and clarity.
Correction: This story has been corrected to reflect that Selinger helped research customer behavior for the development of Amazon's product recommendation system.