Time in the day

If you don’t plan your time,  someone else will. 
This old adage is certainly true for Data people (I like that phrase to cover everyone from analyst to planner,  allocater, Data Scientists,  whatever your taste  may be)
If you leave time ‘open’  someone else will fill it with things they need.  
Is this the best use of time?  Whose priority is more important to accomplish?  If it’s  not your priority,  why are you spending your time?
Time is not replenishable.