" Nothing is so sad, in my opinion, as the devastation wrought by age.
My poor friend. I have described him many times. Now to convey to you the difference. Crippled with arthritis, he propelled himself about in a wheelchair. His once plump frame had fallen in. He was a thin little man now. His face was lined and wrinkled. His moustache and hair, and hair, it is true, were still of a jet black colour, but candidly, though I would not for the world have hurt his feelings by saying so to him, this was a mistake. There comes a moment when hair dye is only too painfully obvious. There had been a time when I had been surprised to learn that the blackness of Poirot's hair came out of a bottle. But now the theatricality was apparent and merely created the impression that he wore a wig and had adorned his upper lip to amuse children! "

― Agatha Christie , Curtain (Hercule Poirot, #34)