Visible crew/equipment: A boom mic is briefly visible when Frasier is talking with Kate in the hall. (00:11:09)
Revealing mistake: Towards the end of the episode, as Frasier is on the lounger by the windows, a power cord is on the ground going through the far left window (where glass should be), possibly going to the lamp.
Revealing mistake: Frasier, Roz and Ben are sitting at a table in Cafe Nervosa. However, as the camera is panning out when Ben sits down you can see the outside of Cafe Nervosa because the wall is only a small partition. The camera zoomed out too far. (00:06:30)
Revealing mistake: When Frasier and his guest are standing up to leave, the girl behind the counter is watching them for her cue to come over.
Revealing mistake: Even though she has customers in front of her, the barista can be seen watching Frasier and his guest as they are talking, so she can see her cue to come over.
Factual error: When the barista hands an umbrella to Frasier's guest we can see she is wearing platform flip-flops. Health code in Seattle forbids open-toed footwear for employees in food service establishments, which would include a coffeehouse.
Boo! (a.k.a. I'm With Her) - S11-E16
Continuity mistake: In the first scene after Niles walks in and takes his coat off. The left-hand side of his shirt collar alternates between tucked underneath his jacket and sitting outside it.
You Can Never Go Home Again - S3-E24
Continuity mistake: When Frasier turns up to the office on his first day, having never met Roz before, he has the briefcase that Roz got for him as mentioned by Roz and Niles 'Fool Me Once, Shame on You, Fool Me Twice...'. How can this be if they've never met before?
Continuity mistake: Marty throws his coat on the stairs, but it moves to the landing.
The Show Where Lilith Comes Back - S1-E16
Visible crew/equipment: Halfway through the episode the boom mic is visible at the top left of the screen above Lilith. (00:10:00)
Rooms With a View (2) - S10-E8
Character mistake: In the x-ray on the right, the x-ray is flipped. The heart should be displaying on the right.
Visible crew/equipment: As Frasier walks into the kitchen near the start you can see a crew member with arms folded at the side of the table on the other side of the lamp. (00:03:55)
Continuity mistake: Frasier is opening a bottle in the kitchen while talking to his father. He takes the cap off the same blue bottle twice. (00:05:07)
To Kill a Talking Bird - S4-E14
Visible crew/equipment: After Frasier starts the fireplace and it scares Niles' bird, you can see the hands of a bird handler by the stairs on the upper right of the screen. (00:12:21)
Goodnight, Seattle (2) - S11-E24
Continuity mistake: When Eddie eats the wedding ring at Martin's wedding, there's no food on his plate, next shot there is.
Continuity mistake: After Martin lowers his chair and gets the bag of pretzels it cuts back to Frasier and you can see the bag still on the coffee table. Then it cuts back to Martin and he has the bag. (00:06:16)
Revealing mistake: It's clear the "Manchester" pub scene was filmed in the United States, as the pint glasses used are American pints and not imperial pints as used in the UK, which are approximately 20% bigger.
Continuity mistake: When Frasier is asking Noel for a favor, Frasier sets papers down on the desk which move from place to place and even disappear and then reappear between camera shots.
The First Temptation of Daphne - S9-E3
Revealing mistake: Frasier and Martin are arguing in the kitchen about the cricket. Martin opens the fridge to grab a beer and slightly bumps the fixed island in the kitchen, which moves.
Revealing mistake: After Donny puts the phone onto speaker you can see him deliberately wiping the mustard from the sandwich across his left cheek to prepare for the gag at the end of the scene. (00:06:45)
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.