How do smart and successful people maintain sanity and manage their time, career, and lives? originally appeared on Quora - the knowledge sharing network where compelling questions are answered by people with unique insights.

Answer by Nela Canovic, productivity hacker, writer, and Silicon Valley entrepreneur, on Quora:

Based on what we see and hear, it seems that successful people are very selective about everything:

Their time.

Successful people become experts at time management. Why? Because they have to. Just like the rest of us, they also have only 24 hours in a day. To ensure that they make progress towards their personal and professional goals, they need to know how much time goes into which bucket. Often they will:

  • Keep a detailed schedule for work, personal, and social life.
  • Use some sort of time management technique (for example, the Pomodoro technique) to maintain focus when working.
  • Block off times when they don't want to be disturbed and switch their phones to Airplane mode so they aren't distracted when they need to concentrate.
  • Delegate and outsource tasks they don't need to be doing (like administrative tasks, etc.) which buys them time to dedicate to what's relevant to them.

Their circle of friends.

You've heard of the phrase that we are the average of the five people we spend the most time with? It really does make sense. If we select friends based on our common interests, our values, the things we consider important to our personal growth, as well as how we value time, knowledge, and friendship, we invest in people who will help us grow as human beings. Conversely, if we surround ourselves with people who don't respect their own time (and therefore won't respect ours), who drain our energy, who are negative and only like to complain, and who exemplify a "fixed mindset" instead of a "growth mindset," we will find ourselves struggling to understand why we don't feel happy and energized after spending our free time with them.

Their deep work.

Very often successful people do their deep work early in the day, when most people are still fast asleep. For many of them, this becomes part of their morning routine, and they prefer to get some work done before the day gets busy. Deep work is what your analytical brain does that requires the most concentration to perform the most complex tasks. Some scientists call this time of day the brain's peak performance time, and it's roughly 2-4 hours after we wake up. So, for example, if you wake up at 6, your peak times are between 8 and 10 AM. You can block this time off to finish up your most important work.

Their downtime.

With very few exceptions, you won't hear successful people saying they spend hours in front of the TV, watching show after show, needing to be entertained. Maybe because they don't practice passive forms of entertainment. Maybe because they select activities where they can do things that are fun, but that require them to be active: playing chess, cycling, reading, playing an instrument. Or maybe they just enjoy taking a power nap for 30 minutes to boost their energy and give them some much needed rest.

Their physical fitness.

Being healthy and fit is critical to achieving success in every area of our lives. The important thing is to choose some type of physical activity that can be done consistently. It doesn't have to be a 2-hour workout at the gym, and people who are successful often are incredibly busy so they don't have that much disposable time. Shorter workouts can work just as well to get an energy boost; it can be something as simple as a 20-minute morning yoga routine, some time devoted to cycling, a half-hour run through a nearby park, or even a quick power walk in the morning before getting in the shower.

Their sleep.

Successful people don't underestimate the power of sleep. Chronic sleep deprivation can reduce cognitive abilities, impact concentration, and can even reduce your IQ. The amount of sleep everyone needs will be different, but an average of 7-8 hours is what sleep experts say is optimal. There are ways to get into the habit of going to sleep at regular times each evening, for example by following a nighttime routine of setting a bedtime alarm to go off about 30 minutes before it's time to sleep, turning off all electronics, going for a short 20-30 minute walk in the neighborhood, and having a hot cup of tea to signal to the body that it's time to unwind.

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