Guests always walked out of the Winslow's front door and then to the left, but in the picture that is shown as the Winslows' home, there is no walkway to the left. There are a few stairs outside that lead up to the front door, but walking to the left after exiting through the front door would only lead into a wall.
In the first episode, outside of the front door is a little hallway leading outside. From the second episode on, the hallway was a porch.
Carl's law-enforcement duties change throughout the series. Sometimes he does detective work, staging stings and going undercover. Sometimes he's a regular beat cop. It depends on the need of the episode.
When looking at the Winslow house from the street, the front door appears on the far left of the facade. The interior set shows that a stairway and additional rooms should appear to the left as you walk inside. This would not be possible given the layout of the exterior.
In Fast Eddie Winslow, the Winslows' address is 263 Pinehurst which later changes to 263 Elm in Cheers Looking at You, Kid.
Whenever the exterior of Rachel's Place is shown, the spinning sign is obviously animated.
Judy Winslow suddenly disappears in season 5 with no explanation; from then on, the family acts like she never existed.
The younger daughter is different in the pilot episode than from then on.