"See then that you walk circumspectly, not as fools but as wise, redeeming the time, for the days are evil." ~ Ephesians 5:15-16 (NKJV)
I've been thinking about this passage quite a bit recently, but in a different way than perhaps St. Paul meant. Time is the one gift given to everyone equally. We all have 24 hours in a day - plumbers, senators, musicians, students. Some of us work 9-5, some work third shift, some work around the clock (moms, anyone??). Whatever our main schedule, though, we all have "undesignated" time - breaks, time between one activity and another, or even time we set aside as "free time." I'm interesting particularly in small bits of undesignated time, such as (in my case) the five or ten minutes between classes and lessons.
What we do with that undesignated time goes a long way toward determining our success at what we do. Recently I've found that if I have a small amount of undesignated time, I can focus on a small task, or a small part of a larger task, and feel that I've accomplished something useful. For example, I can practice a few bars, or a page, of a larger work that I am learning. I could answer two or three specific emails that need thoughtful responses. I could pick up one room of our house. Those five, ten, or fifteen minutes suddenly become quite useful and productive.
What I avoid when focusing on a small, attainable task is the "mental repose" of tuning out for a few minutes and playing 2048 (my latest corollary to "Clash of Clans"), or sitting around wishing I had more time to "really accomplish something."