Continuity mistake: When Daphne mentions she had a dream about a gymnast, she is looking at Frasier, but a quick shot change and her head is turned 180 degrees looking at Niles. This couldn't have happened in real time.
Continuity mistake: Niles and Frasier are looking at books trying to figure out Frasier's dream. When Daphne and Marty come in the door, the shot shows that the book that was on the end of the table has moved quite a distance and is now in front of Niles.
Continuity mistake: Frasier is leaving the booth - Roz is standing there holding several tapes in her hand. When the shot goes back to her, she has papers in her hand and there's no sign of the tapes. In the next shot, the tapes are suddenly on top of the tape machine.
Audio problem: As Frasier says, "Well, let's shoot it to the news," we can see his reflection in the booth, but his lips aren't moving as he speaks.
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.