Continuity: At the beginning of episode # 4.10, "Ye Olde Shoppe Teacher", Tim's lopsided toolbox that he made turns 180 degrees as Jill pushes it away. As Jill and Tim are talking, it turns back. Then it turns 180 degrees again just before Tim briefly leaves the room.
Crew or equipment visible: In one scene of the episode where Tim tries to get rid of the woodpecker, he wears a black helmet outside. Several studio lights are reflected in the helmet.
Continuity: When Tim and Al go to a singles' bar to find Al a date, Al is wearing a ring on his left ring finger.
Errors made by characters (possibly deliberate errors by the filmmakers): Al's girlfriend, Ilene is first introduced as Ilene Markum. But in 'Dream On' the credits says that her character is Ilene Martin.
Miscellaneous: Jason's actor, Jarrad Paul is sometimes spelled as "Jared Paul" in the credits.
Miscellaneous: In some episodes, Sherry Husey's character, Ilene is sometimes spelled as "Eileen" in the credits.
Continuity: Jill's mother says she has 5 daughters, but 6 of Jill's sisters are mentioned in the series.
Revealing mistakes: Although it is never shown, it is made clear throughout the series, that the Taylors' driveway is in the front of the house, out the front door. However, the garage is clearly opens towards the back of the house.
Continuity: In one episode Wilson recalls Tim and Jill as newlyweds who had just moved in and were always fighting. However in another episode a flashback shows that they had just moved in when Randy was a baby, since Randy is the middle child they had to have been married a few years and therefore were not newlyweds.
Continuity: In the episode, 'Karate Kid', Wilson says that he wrote the book 'The Psychophysiological Indices of Amorous Connections Among Termites of the Southwest'. In the episode 'Wilson's Girlfriend', that book was given as the title of Jill's psychology professor. However, in both episodes, it had only managed to sell 4 copies.