Before I delved into DW, all I knew about it was that, the Doctor somehow changed his appearence, he was old and young, and Tom Baker.
Back in the '80s, I had a friend who was into a lot of SF and comics but not a Who
viewer. I often talked to him about the show, and explained it to him, but when he first saw the cover of a book that showed the faces of all six or seven Doctors, he was surprised at how different they all looked. He'd known that the role had been recast multiple times, but he'd assumed they cast similar-looking actors.