How old were Steve and Charley supposed to have been? Fred MacMurray was 53 in 1960 and Bill Demarest was born in 1892, yet the characters each seemed to be about 10 years younger. Also Chip was 7 when the show started, yet I remember that when they went to color in 1965 he was 13. And Stan Livingston was about 15 by then in real life.

I think Chip had a growth spurt, so they made his character age a couple of years. When Ernie was a neighbor in the black and white episodes, he and Chip were supposed to be the same age. Then, all of the sudden, Chip was a couple of years older and a lot taller than Ernie.

you're right. also since they filmed all of fred macmurray's scenes first they would have had problems if one of the kids had a growth spurt between the time of the original filming and when they filmed the rest of the scene without him.