Retirement and the Christian - Part 1

How should Christians think about "retirement"? My mid sixties seem so far away, but each year seems to go faster than the one before. Many of you are closer to "retirement" or have already entered that status. How does one think Christianly rather than culturally about the recent invention of retirement? Bob Rayburn says:

It is certainly fair to say that it is not obvious in the Bible that it is our Heavenly Father’s intention that we should work until we are 62 or 65 years of age and spend the remainder of our years touring the United States in our RV (that is, if we had a defined benefit retirement plan that has not gone bankrupt and we can afford the gasoline!).

Here is a challenging video clip by John Piper on retirement -- "DON'T WASTE YOUR RETIREMENT.