Age is only a number, a cipher for the records. A man can't retire his experience. He must use it. Experience achieves more with less energy and time.
Approach each new problem not with a view of finding what you hope will be there, but to get the truth, the realities that must be grappled with. You may not like what you find. In that case you are entitled to try to change it. But do not deceive yourself as to what you do find to be the facts of the situation.