Continuity mistake: Marie and Frasier are sitting on the couch when Marty comes home, and her arms noticeably change position as the shot changes. Then, a few shots later, she has her hands on her legs above her knees, but in one quick shot her hands are wrapped around her knees - without enough time for her to have changed naturally.
Continuity mistake: In the opening scene, Roz and Frasier are in Cafe Nervosa, and she is snoozing, while a half-eaten muffin sits in front her. As she wakes up and talks to Frasier, the muffin appears whole again. She leaves and Martin comes in and takes her seat. A shot then shows the muffin as half-eaten again, even though no one has touched it.
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.