Continuity mistake: Early in the show, Frasier is at home - the rest of the gang have surprised him with a birthday cake. In one shot the candles are burning on the cake, in the next Frasier is cutting the cake and the candles have disappeared, with no time allowed to remove them.
Continuity mistake: Fairly early in the show Frasier has his dad call the police station to ask about a female officer Frasier is interested in. Marty asks for her name, hangs up, and gives Frasier a lot of information about Maureen that he couldn't have possibly learned in that short a time.
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.