Throughout the seasons Veronica's apartment switches from the first floor to the second floor.
Veronica's (Kristen Bell) dog, Backup, changes after the pilot episode, Veronica Mars: Pilot (2004). The dog in the pilot is a brown American Pit Bull Terrier but was recast for the rest of the series. This was done to avoid dealing with Backup One's dog trainer, as their lack of preparation for the pilot shoots delayed production a lot.
In season one it is said that Melissa Hoover's party was on Dec. 7, 2003. In season three Veronica (Kristen Bell) tells Parker (Julie Gonzalo) the party was an "end of the year bash, summer 2004".
The time of the bus crash in season 2 is first given as 4:20pm in episode 2.2, Driver Ed (2005), but in later episodes, the time of the crash is given as about 7:03 PM.
Throughout out the series, it's clear that the actors/actresses portraying teenagers are actually in their 20s+. This is done as to not interfere with the schooling of real teenagers and to give the general viewing audience who are teenagers themselves someone they can look up to.
While Logan is editing the tribute video to Lilly, among the video clips is one that shows her as a little girl between the age of 5 and 7 at Legoland California. Legoland California wasn't in operation until 1999, which means that Lilly would had to have at been least 10 or 11 during the visit, making her too old to have appeared in the aforementioned clip.
It was said in a season one episode that Lianne (Corinne Bohrer) graduated from high school in 1979; however in episode 2.9, My Mother, the Fiend (2005), it is said she was still in high school in 1980.
In episode 2.3, Cheatty Cheatty Bang Bang (2005), we see in the phone book that Wallace & his family live at 2414 Rialto Way, however in episode 1.16, Betty and Veronica (2005), Veronica (Kristen Bell) says Wallace (Percy Daggs III) lives on the corner of Pleasant Valley and Marigold.