“In one study, elite violinists had separated themselves from all others by each accumulating more than 10,000 hours of practice by age 20. Thus the rule. Many elite performers complete their journey in about ten years, which, if you do the math, is an average of about three hours of deliberate practice a day, every day, 365 days a year. Now, if your ONE Thing relates to work and you put in 250 workdays a year (five days a week for 50 weeks), to keep pace on your mastery journey you’ll need to average four hours a day. Sound familiar? It’s not a random number. That’s the amount of time you need to time block every day for your ONE Thing. More than anything else, expertise tracks with hours invested. Michelangelo once said, “If the people knew how hard I had to work to gain my mastery, it wouldn’t seem wonderful at all.” His point is obvious. Time on a task, over time, eventually beats talent every time. I’d say you can “book that,” but actually you should “block it.”