1 Chronicles 29:28
"And he died in a good old age, full of days, riches, and honour: and Solomon his son reigned in his stead."
Most people do not enjoy talking about age when they get to a certain age. A common joke is that you never ask a lady her age, and the reason is because most women as well as men don't like to think they are getting old. Old age does come whether we like it or not, and your goal should be to live to old age in a Christian manner.
David graced old age. Old age was not a death sentence to David, but his old age was something he could enjoy because he had lived his life according to the Word of God. Certainly, David made some mistakes in his life that I'm sure he wished he could undo, but on the whole he lived his life in such a way that when he died he had more satisfaction with how he lived than he had regrets. David truly died the way a Christian should die. The verse above shows us how he achieved this.
First, he died in a "good old age." In other words, David enjoyed every stage of his life. You will never die in a "good old age" if you don't learn to enjoy each stage of life. Stop trying to be younger or older than you are and enjoy the stage of life you are in. Each stage of life has its blessings and curses, but those who enjoy life to its fullest are those who enjoy each stage of life.
Second, David's life was "full of days." In other words, he enjoyed life to its fullest. He didn't hibernate in his palace, but he enjoyed what God gave him to enjoy in his life. I believe it is important that you enjoy life to its fullest. One way you do this is to be sure to serve the LORD. You cannot enjoy life to its fullest unless you serve the LORD. Furthermore, enjoy the pleasantries life gives. Enjoy your family by spending time with them. Enjoy the blessings God has given you. Have time where you enjoy your hobbies. The balanced Christian life is living life to its fullest. Certainly, you should serve God, but also enjoy the pleasantries of life along with serving Him.
Third, David died with "riches." David did not strive to be rich, but he became rich because he learned the value of saving while he was younger. I completely understand that everyone will not be rich when they get old, but everyone can learn the value of setting aside a portion of their finances when they are younger to be able to use when they are older. If you are going to enjoy life, you better learn to set aside for retirement. Don't spend every penny you get, but learn to save money for retirement. As my uncle taught me years ago, you can have little now and a lot of things later, or you can have a lot of things now and have nothing when you get older. Be the wise Christian who sets aside for retirement.
Fourth, David died with honor. You will never die with honor if you live a life of sin. David lived his life serving God, and that is why he died with honor. One of your goals should be to die with honor. Don't live a life that will cause you to die a dishonorable death. Live your life realizing at any moment you could die. Always remember before you choose to commit sin that if you died while doing it you will die a dishonorable death. Live your life in such a manner that you would not be ashamed if you died while doing any action.
These four things are what God desires for every Christian. None of these things are out of reach for anyone. If every person will dedicate their life to live for God, they will find that these four areas will be said about them when they die. If you lack in one of these areas, then change that area of your life now and start working on improving it so that people can see that serving God is a worthy lifestyle.