Chorus from the song "Question!":
Do we, do we know
when we fly...
when we, when we go...
do we die?
Thinking about life after death is useful for life right now.
If we are convinced that "what we do in this life echos in eternity" (Gladiator), then we will live better right now.
In particular, our mortality should be a constant source of realistic, humbling perspective.
The fact that we will die should inspire us to take care of business with God.