I never heard of an old man forgetting where he had buried his money! Old people remember what interests them: the dates fixed for their lawsuits and the names of their debtors and creditors.
My kid could get a bad X-ray and I could get a call from the doctor saying I have something growing in my bum and that would change my perspective on everything instantaneously on what is and what is not important.
My favorite traditional Christmas movie that I like to watch is All Quiet on...
You do have to change things as warfare changes.