Birdies, Bogies, and Baxter - S4-E7
Continuity mistake: When at the country club table the swimmers in the background change from scene to scene.
Samantha's Thanksgiving to Remember - S4-E12
Continuity mistake: When Darrin is at the table with Phineas and John Alden the turkey changes positions. The legs are pointed towards Phineas then in side shot turns away then back.
It's So Nice to Have a Spouse Around the House - S5-E5
Continuity mistake: The exterior of 1164 Morning Glory Circle is fake. It is not the exterior we have seen for years. They often go to a pained forested background with the fake exterior.

Samantha's Thanksgiving to Remember - S4-E12
Visible crew/equipment: While Sam is defending Darrin during the trial, just as she mentions their absurd belief that if someone speaks differently it's a sign of witchery, the white chalk T-mark is visible on the floor under the desk, where Phineas is sitting. It was not there in previous shots. (00:19:25)
Continuity mistake: When Ava is cat dancing with Darrin and Sam comes over and removes Darrin's whiskers, the guest with a turban costume changes positions.
Naming Samantha's New Baby - S6-E6
Factual error: When Mr. and Mrs. Stephens are driving in the convertible. In second shot, there are at least 2 tall palm trees along the road. Morning Glory Circle is supposed to be a NY town. There are no palm trees growing in NY. It's obviously shot along a CA road.
Other mistake: This is a remake of season 1 episode when Paul Lynda makes his first appearance as Harold the driving instructor for Samantha.
Suggested correction: This is trivia at best, but the episode isn't really a remake of an earlier episode. Here Samantha teaches Uncle Arthur (Lynde) to drive and in season 1 Harold (Lynde) taught Samantha to drive. But the same actor playing multiple roles in a series is never a mistake.
Double, Double, Toil and Trouble - S4-E4
Revealing mistake: As Serena gets hit by the pie her real blonde hair shows underneath, also, she wears minimal make-up for the only time.
Santa Comes to Visit and Stays and Stays - S6-E14
Plot hole: Mrs. Kravitz, while standing in the Stephenses' front doorway, sees Santa Claus and assumes that it's Darrin in costume. However, the very next shot shows Santa exiting the kitchen (around the corner from the front door) and starting up the hallway toward the living room. There is no possible way Mrs. Kravitz could have seen him when she said she did. (00:09:30)
Visible crew/equipment: Right after Samantha, Darrin and Tabitha pop out of the living room, the shadow of what looks like a camera rolling backwards can be seen on the floor. (00:21:55)
I, Darrin, Take This Witch, Samantha - S1-E1
Continuity mistake: When Darrin collapses after Samantha zaps him the drink, in the next shot the glass is on the table with the straw across the top.
It Takes One to Know One - S1-E11
Continuity mistake: When Larry tells Darrin that he is going home, the blinds behind Darrin are shut, however in the close up of Darrin, the blinds are open.
Revealing mistake: When Sam and Endora are sitting on the wing of the airplane, you can see folds in the blue backdrop for the sky.
How Green Was My Grass - S4-E24
Continuity mistake: Before this episode (and after as well) Darrin and Samantha give their address as 1164 Morning Glory Circle, however in this episode, when Darrin slams the door, the '9' in 192 on their address spins around to make 162, hence the angry neighbor at 162 saying that his grass was installed at the Stevens' by mistake.
Other mistake: Although Diane Murphy played "Annabelle", she is listed in the closing credits as having played "Diane". (00:25:00)
Open the Door Witchcraft - S1-E28
Deliberate mistake: Sam and Darrin are "trapped" in the garage; however, you can see a side door.
It Shouldn't Happen to a Dog - S1-E3
Continuity mistake: Samantha's hair goes from neat to messy and back again during the chase scene in the alley.
Deliberate mistake: The drunk that is always in the bar in New York is the same drunk in Salem that sees Sam twitch the witch on the signs from an old hag to a young witch resembling her.
Samantha Goes South for a Spell - S5-E2
Continuity mistake: The same kitchen door that led to a rather spacious laundry room in "Double, Double, Toil and Trouble" (season 4) now leads to an ordinary utility closet. (00:02:20)
Revealing mistake: When looking out of the Steven's kitchen window, the view outside changes completely during different episodes of the show.