And it doesn’t mean that you should always feel detached either. It just means that you should be capable of practicing detachment when required. To be attached is to live in the fear that what you want will not materialise and traps you in a continuous state of desire.
Consequently, the types of foods you eat, and when you eat them, determine your ability to focus at work. Your ability to sleep well (by the way, it’s easy to sleep well when you get up early and work hard) is also essential to peak-performance. Rather than managing your time, then, you should really be focused on managing your energy. Your work schedule should be scheduled around when you work best, not around social norms and expectations.