Continuity mistake: Martin goes out to a baseball game with a famous writer that Frasier and Niles admire. While he is out, they read one of his books he accidentally left behind. When the author returns, he ends up holding the pages of the book in his hand, whilst standing in front of the fireplace. In one shot he is holding them in his left hand, but when the view cuts to another angle, he has them in his right hand. This occurs just before he goes outside to throw the pages off the balcony. (00:20:25)
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.