John Piper has a free (and not-too-lengthy at 29 pages) e-book for you to download entitled "Rethinking Retirement: Finishing Life for the Glory of Christ." Here are the first few paragraphs to get you started:
"Finishing life to the glory of Christ means finishing life in a way that makes Christ look glorious. It means living and dying in a way that shows Christ to be the all-satisfying Treasure that he is. So it would include, for example, not living in ways that make this world look like your treasure. Which means that most of the suggestions that this world offers us for our retirement years are bad ideas. They call us to live in a way that would make this world look like our treasure. And when that happens, Jesus is belittled.
Resolutely Resisting Retirement
Finishing life to the glory of Christ means resolutely resisting the typical American dream of retirement. It means being so satisfied with all that God promises to be for us in Christ that we are set free from the cravings that create so much emptiness and uselessness in retirement. Instead, knowing that we have an infinitely satisfying and everlasting inheritance in God just over the horizon of life makes us zealous in our few remaining years here to spend ourselves in the sacrifices of love, not the accumulation of comforts."
Go here to download the rest.