Continuity mistake: While Marty and Daphne are watching the basketball game on TV, he says "it's completely different", the remote suddenly appears on the table beside him; it wasn't there before and wasn't in his hand. A couple of shots later, when he yells "unbelievable!" it's gone again.
Hot Ticket - S6-E4
Continuity mistake: When Trevor asks Frasier and Niles about "the hat scene," you can see Frasier's hands resting on the bar away from his glass. In the next shot, his hands are clasping his glass.
The Show Where Sam Shows Up - S2-E16
Continuity mistake: At the end of the episode after Sam mentions stewardesses he claps his hands, and his seat belt (which was caught on something) moves across his chest to the regular position. Cut to a wide shot of the car and Sam's seat belt is back to the position it was in before. (00:21:05)
Hot Ticket - S6-E4
Continuity mistake: Frasier and Niles are talking about getting tickets for the play. On the table next to Marty's chair there's a newspaper that changes position noticeably during their conversation. Neither of them touched it and Martin is not in the scene.
Docu.Drama - S8-E16
Continuity mistake: When Martin is eating at the coffee table, you see the front of the tomato sauce/ketchup bottle, then the back, then the front again. Also the spice that was on the table moves without anyone touching it.
Dad Loves Sherry, the Boys Just Whine - S4-E9
Continuity mistake: When Sherry brings in the bottle of wine, it's in a paper bag which is twisted around the bottle when she puts it on the coffee table. The next shot shows the bag has been loosened around the bottle and is quite wrinkled. No one touched it in that short time.
To Thine Old Self Be True - S7-E20
Continuity mistake: Frasier goes to get a newspaper out of the curbside kiosk, and catches his jacket in it. He places the newspaper to his right on top of the rack beside it and the shot changes to Regan coming out of the florist behind him. Then we see the newspaper in his left hand, without having time to have picked it up.
Continuity mistake: As Roz is introduced to Clint, there is nothing on the console where Frasier is standing. But as the scene progresses, a clipboard suddenly appears there, without human assistance.
Perspectives on Christmas - S5-E9
Continuity mistake: Daphne puts a couple of Christmas bags on Marty's chair; the one facing the camera has a Santa on it and behind that are pieces of pink paper sticking up about 6 inches. The pink paper is sometimes visible, and sometimes isn't, as the scene progresses, from the same angle.
Dad Loves Sherry, the Boys Just Whine - S4-E9
Continuity mistake: When Sherry first meets Frasier and Niles, she puts her coat down towards the center of the couch. A few shots later, although no one has moved it, it shifts to the left and her purse, which wasn't visible before, can be seen.
Someone to Watch Over Me - S2-E19
Continuity mistake: Frasier and Roz are in his booth and Roz puts her chocolate bar on the counter. While Frasier is on the radio, we sometimes see it at his left elbow and sometimes it is not, even though the angle doesn't change. (00:02:20)
Continuity mistake: Frasier gets caught in Daphne's Room for the second time and crouches down beside her bed with the quilt over his head. He then sneaks into the bathroom - the quilt is left hanging over the edge of the bed. Shortly afterwards he runs out of the bathroom and the quilt is now folded over, completely on top of the bed, even though no one went near it. (00:13:30)
When a Man Loves Two Women - S6-E21
Continuity mistake: Daphne and Marty are arguing about Cassandra and Faye. As the shot goes from one to the other, the spout on the milk carton goes from opened to closed and back again. (00:09:35)
Continuity mistake: Martin is listening to Donny talk to Niles in his office. At one point Marty has his right hand up to his face but in the next shot his hands are laced together, resting on his stomach, with no time for a natural change. (00:09:30)
The Seal Who Came to Dinner - S6-E8
Continuity mistake: Frasier and Niles are in Cafe Nervosa talking about Niles' Dinner Party. During the scene, sometimes the lid of Niles' coffee up is on, and sometimes it is off, even though Niles never touches it. (00:02:35)
Merry Christmas, Mrs. Moskowitz - S6-E10
Continuity mistake: The first time Helen and Faye try to leave, Helen tucks her purse under her left arm but in the next shot we see her move the purse from her right to her left arm again.
Continuity mistake: Frasier knocks the drinks over in Manu's newspaper stand. They had been sitting on a plastic tarp over some newspapers. In the next shot the plastic tarp is draped much differently, covering the papers more. No one touched it in the meantime.
Whine Club - S7-E17
Continuity mistake: When Niles and Mel are in his dressing room, Mel puts Niles' jacket on the table in the center. A couple of shots later, the jacket changes position, even though neither of them touched it.
The Dog That Rocks the Cradle - S7-E5
Continuity mistake: When Roz's date Ted returns her purse to her apartment, Bulldog answers the door. He barks at Ted and Ted nervously drops the purse. We see Bulldog close the door. He should have picked up the purse first, or he wouldn't have been able to close it. We do see him drop the purse in a chair as he heads to the kitchen, but we never actually see him pick it up.
Continuity mistake: When Lilith arrives at Frasier's, she is moving her hands, rearranging her wrap and her purse is in her left hand. Without time for her to change it, in the next shot her purse is in her right hand.
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.