Continuity mistake: Marty, Frasier, Niles, and Daphne are in Frasier's apartment, talking about Marty moving in with Niles - M.'s beer can and remote are sitting on his little table. In one shot they are quite close together, but in the next the can has moved about six inches forward.
Continuity mistake: In one of the sequences where Niles and Shenkman are running in and out of the bedroom, Shenkman sprays perfume around the bed. The roses that were on the pillow have now completely disappeared and never reappear although neither Niles nor Shenkman touched them.
Continuity mistake: Niles is filming is father in his recliner, trying to record his life story for posterity. Marty fakes a heart attack or death - and lies back in his chair with his left arm by his side. In the next shot his arm is crooked up around his head, but with no time for him to have moved it.
Continuity mistake: After calling Martin the "Sultan of Brunei," Frasier grabs his wine glass with one hand on the top and walks out of the kitchen. In the next shot when he is coming out he is holding it by the neck and there was no time for him to change his grip.David Mercier