Continuity mistake: There was an episode in which Martin attempts to end a feud between Frasier and Niles by telling a story about his detective partner. He starts with the line, "I never had a brother...", but in the episode about Frasier's cousin Nikos getting married, Martin's brother Walt was introduced.
Continuity mistake: During the opening credits, Frasier is playing the piano and Martin is going through papers on the table. When Marty says "I don't know, Eddie, must you?" there is something pink lying on the table. The shot goes back to Eddie and then back to the table, but the pink item has disappeared.
Continuity mistake: Near the start of the show, Roz is in her booth at KACL and takes out her lipstick and compact - we see her uncap the lipstick. Then Niles comes in an Frasier reintroduces them, and we see her uncap the lipstick again.
Space Quest - S1-E2
Continuity mistake: Frasier (and later the others) come back to his apartment to avoid the rain - they shake off umbrellas, and we even hear the storm at the very start of the scene. However there's no rain on the balcony - can't be covered, as we see in "Call Me Irresponsible" during the obligatory sex scene that when it's raining the balcony gets soaked.
The Good Son - S1-E1
Continuity mistake: During the first episode of Frasier there is a painting of some vases in Frasier's apartment which is at the end of the hall leading on to Daphne's Room. In this episode the painting has a red and purple background, however in 'Here's Looking at You' (S1, 2 mins 52 secs) the exact same painting is now red and blue. It remains this new colour for the entire 11 seasons. (00:06:50)
The Good Son - S1-E1
Continuity mistake: In the scene where Daphne first comes to the apartment, the beer can and remote control on Martin's side table change positions between shots.
Continuity mistake: When Frasier and Niles are eating the steaks at the restaurant that Martin brought them to, in some shots you can see Frasier's baked potato, and in others from the same angle it is not visible.
You Can't Tell a Crook by His Cover - S1-E15
Continuity mistake: When Frasier and Martin are looking at Frank examining the bowl, the cards on the table change position.
A Midwinter Night's Dream - S1-E17
Continuity mistake: When Martin is giving Niles ideas on how to win Maris back, the food on Martin's fork changes between shots.
The Good Son - S1-E1
Continuity mistake: At the beginning of the show, when Roz is telling Frasier the mistakes he's made, the clock shows 4:52. However, after she says "you kept referring to Jerry.as Jeff", the clock is reading 4:50.
Continuity mistake: While Martin is saying grace, Eddie is sitting right on his backside staring at Frasier, who yells "will you stop staring!" The next shot, from behind Eddie, shows him noticeably leaning over on one haunch, even though there was no time for the change.
The Good Son - S1-E1
Continuity mistake: When Martin lies back in the chair for the first time, it changes how slanted it is in the first two shots.
Continuity mistake: Before they begin supper, Marty asks the boys if they still say a prayer before eating. His hands are clasped together in front of him, but in the next shot they are folded over each other.
The Good Son - S1-E1
Continuity mistake: Near the end of the show, when Roz is telling Frasier about Lupe Velez, the wall clock in her booth shows the time to be 3:45. About 5 minutes pass, although the story only takes a couple of minutes, and there is no other action in the scene. The clock actually goes backward after that, showing 3:50 and then about 3:48 in the next shot.
Continuity mistake: In the scene where Niles meets Daphne for the first time she is folding laundry and is holding a tee shirt that switches back and forth from being over her arm to being held in her fingers while they talk.
Continuity mistake: While Daphne is making psychic predictions about Marty's murder case, there is a pencil lying under some photos. In one shot the pencil has disappeared but it reappears again in later shots. The angle stayed the same.
A Midwinter Night's Dream - S1-E17
Continuity mistake: In the opening scene when Daphne and Eric are talking, the dish towel over Eric's shoulder is laid flat in some shots, and is twisted up in others.
You Can't Tell a Crook by His Cover - S1-E15
Continuity mistake: When Frasier and Niles are in the cafe talking about the Topaz Room, the waiter goes from bending over the table to collect the money to upright a few feet from the table instantly.
A Midwinter Night's Dream - S1-E17
Continuity mistake: The time on Niles' musical clock changes time suddenly and frequently between shots, once from 9.00 to 10.55 to 11.25 almost instantly.
You Can't Tell a Crook by His Cover - S1-E15
Continuity mistake: When the doorbell rings Martin leans over to put the cards down, you see him do it twice.
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.