Continuity mistake: When Lilith and Frasier are at Dr. Campbell's (the first time), he makes them tea. A shot shows him preparing it, pouring it, etc. But in the next shot, Frasier and Lilith are already holding their cups. There was not enough time for him to have passed them the cups.
Continuity mistake: Frederick appears in the kitchen to talk to his parents, who are ignoring him. In one shot he is covered with spots and in the next, he only has about half as many. He is supposed to have hives, which I know can appear and disappear quickly, but these look nothing like hives in the first place.
Answer: It equals the record of James Arness of "Gunsmoke" for the actor who's played the same part on TV NOT in a soap opera. If you include soaps there are two main contenders - William Roache, who's been playing Ken Barlow in "Coronation Street" in the UK since 1960. Don Hastings has been playing Robert Hughes in US soap "As the World Turns" since 1960 as well.