Audio problem: Frasier is on the air and is talking to Roz who is in her booth. As he says "Meanwhile, this is Dr. Frasier Crane," we can see his reflection in the glass but his lips aren't moving, even though he is talking.
Continuity mistake: Frasier comes home to find his sherry decanter empty and opens a bottle of wine, which he leaves on the kitchen counter. Niles arrives, wants sherry, and Frasier tells him there is none, saying, "I've opened some wine, help yourself." Niles grabsthe open bottle from the bar area, even though no one had put the bottle back - it should have still been on the kitchen counter.
Continuity mistake: Frasier and Martin are in the kitchen and Marty gets some chips out of the cupboard next to the fridge. As he leans down to pet Eddie we can see a bag of blue chips still in the cupboard - but when he straightens up to talk to Frasier, we see a red bag in the cupboard, not the blue one (the camera angle remains the same).
Continuity mistake: Frasier and Niles are in the kitchen at the cabin. Niles picks up his mug to take a sip, but in the next shot his mug is still on the table.
Continuity mistake: When Frasier and Marty are talking about going to Ronee's cabin, Ronee is sitting on the right side of the couch with nothing behind her. In the next shot, she gets up and we can see a light brown overcoat. This coat disappears again in the next shot, as Frasier answers the door and Niles comes in, carrying the very same overcoat which he places on the right side of the couch, where Ronee had been sitting.
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.