Originally Posted by
Face Of Jack:
“It's a bit weird how people aged back then compared to now! 

”
There are factors such as much better nutrition in modern diets, especially in the crucial development period of childhood, but for the most part I'm not sure if there's really any difference or if people's perceptions of age simply change as they themselves get older. When I was a child I only really recognized three 'ages': child, adult and old person (perhaps teenager too). Now, I can make good guesses of age to within a few years of people up to about 40 - which, perhaps crucially is within my own life-span. From then on, I find it a little harder. I expect that by the time I'm 60 I'll be able to distinguish between 50 and 60 fairly easily.
Also, fashion and appearance have a lot to do with it. Take Hartnell's wig off, shave his head so he doesn't have the old man receded hairline, which is uncommon nowadays because people shave their head to hide natural baldness, give him a good bout of modern standard dentistry and then put him in jeans and a modern shirt and I'm not convinced he would look all that old compared to a modern day person of the same age.