Which Person Will It Be?
Assign Ed or Maria to complete a particular project in May and you will be assigning a different person than if you had made that decision in January.
For example, Ed may be rested and calm in January but impatient and over-eager in May. Maria may be distracted and uncertain in January but focused and confident in May.
We may not notice the changes in them. This is not surprising. It is unlikely that we will have noticed our own changes.
A decision or assignment is not something "out there." It can be highly personal and people are not unchanging commodities. No one steps twice into the same river because both the river and the person have changed..