Other mistake: When Frasier enters the apartment, Martin and Sherry are talking in the kitchen. If you listen carefully to what they're saying, their conversation makes no sense. Martin says something along the lines of "Daphne is really a very nice girl" before suddenly, in a very different tone of voice, he says "You're right, we're not getting enough privacy around here". Seems like a big chunk of conversation was edited out.
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.
Continuity mistake: Towards the end of the show, Daphne, Niles, Sherry, and Martin are in Frasier's bathroom where he is trying to take a bath. He starts talking to Sherry - she is sitting on the ledge at the end of the tub. From one shot to the next she has her left leg crossed over her right, then her right over her left, and then both legs uncrossed. She did not have time to shift her position and there is no "residual movement" that would have been natural had she been fidgeting while he talked to her.
Continuity mistake: When Frasier and Marty are sitting at the breakfast table, talking about the weather, Frasier's newspaper is sometimes folded over and sometimes not, although he never changes it from shot to shot.
Continuity mistake: Marty, Daphne, and Sherry are all shouting at each other around the dining room table - there are two chairs between Martin and Daphne but when the shot changes to Frasier coming in, now Marty and Daphne have no chairs between them.
Continuity mistake: While Daphne and Sherry are arguing, Marty says, "See, I'm regretting that one already", and his rolled up exercise mat, sitting on the table, rotates about 45 degrees.
Continuity mistake: During the bathroom scene where Frasier is in the bath talking to everyone, the bubbles on his face and shoulders change in position and amount from shot to shot.
Continuity mistake: During the breakfast scene Marty's cane is leaning against the table in the same spot, but sometimes there is a bowl of lettuce next to it, and sometimes a bowl of cheese.
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.