Some things are of little importance if waited upon at the last minute. Missing a train at the last minute may mean waiting for the next train. The store closing before you arrive means having to wait until it opens again in the morning. It is sudden, swift, decisive and unbending. It's too late, then.
Life can become so involved with all the busy matters that seem important at the time.
We can put things off until another time because we have time. The day dawns when all these things change and it's too late. God tells us to think about our life as a vapor. It is even a vapor that appears for a little time and then vanishes away. Jesus told the story of a man who thought he had everything to live for - but it was too late.