She looked way more natural in her early episodes and wore Sevier clothes. When she got with Michael she looked pale with too much makeup and her hair dyed pretty much white. Or maybe they'd call it "platinum".
shareIn a long-running TV series, ~everyone looks better in the early episodes, because they are younger, obviously. In the case of Julia Duffy, she was already about 10 years older than the character she was playing. When she became a main character in season two, she was 32 years old, playing someone who was supposed to be in her early 20s. When the series ended she was only a month shy of her 39th birthday, and you'd be hard pressed to find any woman who looked as young/good as she did at the age of 39.
I didn't notice much of a difference in her appearance over the course of the series, aside from her hair style and color. I liked her hair better in her early episodes. The same goes for Mary Frann, especially when she had her hair up, like in this episode from season 3:
https://i.imgur.com/3hGv9tn.png
Julia's hair looks good there too. Eventually both of them went full-on 1980s with their hair, which sucked.
Didn't know Duffy was in her 30s during that run..
And while I agree that just about all actors look better in a long running series, I think Loretta Swit looked better in the middle years of M*A*S*H - one of the few exceptions I can think of.