Continuity mistake: During breakfast, there is a bowl of scrambled egg next to Martin that moves itself around, and at one point the fork in it just vanishes and then reappears.
Frasier's Imaginary Friend - S5-E1
Continuity mistake: When Frasier gets up to get out of the plane seat between the married couple, he is clutching his coat and boarding pass in his left hand/arm but when he reaches the aisle, they are in his right hand.
Selling Out - S1-E9
Continuity mistake: When Frasier and Niles are in the Cafe, Niles says something like "Why do you feel like that?" During this line Niles goes from putting sugar in his coffee to having the mug raised instantly.
Continuity mistake: Marty is sitting at the dining room table and for a couple of shots he's eating potato chips with his right hand; the shot changes to him eating with the other hand, with no time for a natural shift. (00:14:50)
Three Faces of Frasier - S7-E21
Continuity mistake: When the first cartoon is about to be revealed, the cloth over the easel moves up and down between shots.
Continuity mistake: After calling Martin the "Sultan of Brunei," Frasier grabs his wine glass with one hand on the top and walks out of the kitchen. In the next shot when he is coming out he is holding it by the neck and there was no time for him to change his grip.
Continuity mistake: When the vase is broken during the swordfight, notice the way it has been damaged. When Niles comes back down the stairs, the damage to the vase is different.
The Last Time I Saw Maris - S3-E8
Continuity mistake: Frasier and Niles are in the living room talking about Maris. Frasier says, "I was on the mark", and Niles' beer stitches from his right hand to his left from one shot to the next.
Merry Christmas, Mrs. Moskowitz - S6-E10
Continuity mistake: Niles and Marty are in the kitchen and Niles is coaching Marty on how to pretend to be Jewish. While they are talking, the lid on the sugar bowl goes from being on properly to being askew, even though no one touched it.
Continuity mistake: Martin and Daphne are laughing at Eddie who has taken a pill to calm him down - in one shot he has a paw up in the air, but in the next shot both paws are pointing sideways. The shot changes again, and Eddie is back in the first position. He had to time to change naturally.
Continuity mistake: Frasier has left his mug on the table to goes to console Father Mike who has just come out of Kate's office. The next couple of shots of the table show the mug in different positions.
Martin Does It His Way - S3-E3
Continuity mistake: When Martin first brings the sheet of paper out of the box with the lyrics to his best song on it, the paper has a section torn out of one corner. A couple of shots later and the paper is whole.
The Kid (2) - S5-E4
Continuity mistake: Roz and Frasier are in her apartment, talking. Roz is leaning back on her arm, sitting on her bed. In the next shot her hands are in front of her. The items on the bed behind her have also changed positions.
Continuity mistake: Roz and Frasier are in Cafe Nervosa near the start of the show and her sunglasses are on the table. However, in a shot over Frasier's shoulder, they are not there anymore. They reappear in the next shot.
Continuity mistake: When Marty comes into the living room, he puts the container of jerky down on top of the book on the right side of the coffee table. A few minutes later, when Donny takes a piece, the container is on top of the book on the left side of the table. No one went near it in the meantime.
Good Grief - S6-E1
Continuity mistake: Roz is about to show Frasier her video of him feeding Alice - he is sitting in his dad's chair holding a piece of food in each hand. The shot goes back to him and he has both pieces in his right hand - without enough time for him to switch.
Hot Ticket - S6-E4
Continuity mistake: After Sir Trevor leaves the bar and heads for his reception, the level in the drink he left behind goes up even though no one went near it.
Audio problem: When Frasier is in the hall explaining to Kenny and Gil why Poppy has her own show, we can see Poppy through the glass of the door. She is supposed to be doing her show, and we can hear the audio in the background. However, it is obvious that Poppy is not talking at all - she is sitting perfectly still with a very blank look on her face.
Frasier Gotta Have It - S5-E19
Continuity mistake: Roz brings a folder of papers from work, which she puts down on the end of Frasier's coffee table where it lies diagonally for most of the scene except during one shot where it is lying perpendicular to the table.
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.