If you have a to-do list that’s a mile long — or worse yet, no to-do list at all — here’s what you can learn from four successful entrepreneurs about time management. In an interview with Lifehacker, they shared how they work.

1. Max Levchin, Max Levchin, CEO of Affirm and Co-Founder of PayPal

Max co-founded and has invested in hundreds of companies (primarily through my innovation and investment lab, HVF), most notably PayPal, Yelp, Slide, Glow and Affirm.

What’s your best time-saving shortcut or life hack?

I tend to come up with precise routines and repeat them obsessively every day. In perfect detail, every morning at home looks the same. By cutting out the contemplation of what to do next, I achieve extreme efficiencies.

For example, I know it takes precisely 90 minutes between waking up and getting onto my bike. I know how to cut that to 75 minutes if needed. I have a very specific set of steps, and once I find a routine that works, I codify until it’s perfected, minute-by-minute. This works with well with anything that doesn’t require creativity.

2. Arianna Huffington, founder of The Huffington Post, and Thrive Global

Arianna is the founder of The Huffington Post, the founder and CEO of Thrive Global, and the author of 15 books, including, most recently, Thrive and The Sleep Revolution.

What’s your best time-saving shortcut or life hack?

It’s not an everyday time-saver, but it’s something I’ve done a few times, the first when I turned forty. And that’s to do a kind of audit of your long-term to do list. We all have these projects piling up on our on long-term to-do lists, and even when we’re not thinking of them everyday, we know they’re there.

And the ever-increasing weight of them has a psychological cost—they don’t live rent-free in our minds and they take up a lot of space, draining our energy and diffusing our attention. It’s like paying for storage for things you’ll never use.

So what I did in my life-audit was to “complete” these projects simply by dropping them, which was very liberating. So if what you need to get rid of them is to give them a “done” checkmark, then check them off! It was very liberating to realize I could “complete” a project by simply dropping it—by eliminating it from my to-do list.

That’s how I completed learning German and becoming a good skier and learning to cook and a host of other projects that now no longer have a claim on my attention.

3. Carlos Watson, Founder and CEO of OZY Media

Carlos made a career for himself in television and news and for the past three years has been pursuing his own vision for media with OZY Media. He is also the host of Point Taken on PBS, is the editor-in-chief of his own site Ozy.com in addition to the head of the company.

What’s your best time-saving shortcut or life hack?

Believe it or not, the thing that helps me the most is my sexy old school cell phone hands free headset. When I do not have the right head set, I am literally 50% less effective.

 Another tip—I am a believer in clear agendas and deadlines. I also believe that you just do it without fear—make that call, don’t just send an email and hope. Get on a plane and chase down that terrific opportunity, do not just wait for a firm confirmation and then agree to fly out. Go get it! No holds barred.

4. Jason Fried, Founder and CEO of Basecamp

Basecamp was founded 17 years ago by Jason Fried, Carlos Segura, and Ernest Kim. Originally called 37signals. Jason Fried, CEO, keeps things pretty simple as he runs the company. No real to-do lists, no multiple monitors, no alarm clock.

What’s your best time-saving shortcut or life hack?

Saying no. Techniques and hacks are all about managing what happens when you say yes to too many things. All the techniques and hacks in the world never add up to the power of no. Having fewer things to do is the best way to get things done.

I’m very careful with my time and attention—it’s my most precious resource. If you don’t have that, you can’t do what you want to do. And if you can’t do what you want to do, what’s the point?