God is never haphazard, he prepares people for the assignment He has prepared for them.
Even before your assignment is revealed to you, God keeps preparing you.
He takes you through different situation, phases and stages of life as part of the preparation.
This is to build in you the capacity for the assignment.
God will never assign you until He has prepared you.
Also, the phases of the assignment assume new level to the proportion of enhanced preparation.
So, to keep preparing is to keep increasing your opportunities to serve.
When you are unprepared, you remain un-appointable and nonassignable.
To maintain your eligibility in service, keep preparing yourself.