Life priorities allows us to periodically thing about the goals we are pursuing. Are we always pursuing goals from God? Are we sometimes derailed into pursuing vain or empty thing? Ecclesiastes was written by Solomon as he meditated on these things. He concluded that pursuing goals that are strictly "under the sun" (not from God and not of eternal value) we vanity, emptiness, fruitless, etc.
This is not to say that vane things under the sun are not good to accomplish, just that our life focus should not be on such things. Rather, we should be focused on life priorities given to us personally by God.
Life priorities gives us a prioritized list to help us work out the frequent conflicts between the activities and relationships that we experience.
The summary advice is to "Walk in the Spirit" in accordance with Galatians 5.