Continuity mistake: After Mark is found, he runs into Kate's arms and hugs her and her sunglasses fall off her head, but then in the very next shot they're back on her head perfectly. (01:24:50)
Visible crew/equipment: When Tom and Dylan are hanging from the chandelier, there is a shot of the ceiling showing the chandelier coming loose. Then when it cuts back to Tom hanging from the chandelier, in the background behind him is a crewmember holding a boom mic. (00:24:15)
Continuity mistake: When the Baker's first move in and Dylan's family comes to visit, right after Dylan falls off of the Chandelier, Jake throws one of his shoes down (not both). In the next shot, the father is holding both shoes. (00:25:45)
Continuity mistake: When Tom enters the train to search for Mark, it's an Amtrak passenger train but when there's an aerial view of it, it's a commuter train. (01:23:15 - 01:24:15)
Continuity mistake: At the beginning during the breakfast scene, the eggs splatter all over everyone and some gets on Steve Martin's chin and you can see it fall off, they then show a shot of FedEx and then show Steve Martin again and the egg is back on his chin. (00:10:15)
Other mistake: When Steve Martin is seated at the table trying to find a babysitter, there are several quick shots of the phone book as he crosses out numbers, turns the page, etc. The very last shot of the phone book is backwards! While its easy to see the phone book, if you zoom in on the shot, you can clearly see that the tiles, words and letters on the board partially obscured by the phone book are backwards too. (00:53:20)
Continuity mistake: When the kids are about to put Hank's underwear in the meat bucket, Henry and Jake insert cotton-ball type things in their noses. After they do this, we see that there is still a good amount of white sticking out, but in the very next shot, there is barely any white showing.
Other mistake: At the beginning of the film, Lorraine is in the bathroom while her sister is banging on the door outside. Notice how blonde her hair is as she is applying her lip gloss. At the breakfast table a few minutes later her hair is a different type of blonde. This is because Hilary Duff wasn't available at the time of filming the beginning of the movie and her bathroom sequence had to be filmed many months after the filming for the rest of the film had been completed.
Continuity mistake: At school Mike Baker knocks the latte out of the bullys hand, and the latte falls to the floor spilling a bit of drink on the bullys shoe. Yet in the next wideshot of Mike lunging at the bullys legs, the drink cup has vanished and both of the bullys shoes are clean. (00:58:55)
Continuity mistake: When Hank and Nora come to visit, Hank is walking on the sidewalk leading to the house, and we see him take off one of his gloves. In the next shot, he takes off the same glove. (01:10:00)
Continuity mistake: When Mark spills water on Tom, Tom has a big wet patch on his trouser leg. This disappears when he goes upstairs. (01:13:20)
Continuity mistake: When Mark is walking down the hallway on his first day of school, he runs into two bullies. After the bully grabs Mark's glasses he then pulls Mark's hat down. Then, when the other bully is about to pull Mark's hat down the hat is up and perfectly fine. (00:45:25)
Revealing mistake: When Kate is telling the kids that their dad is quitting his job, the boy called Mike looks directly at the camera.
Continuity mistake: In the kitchen when Kyle and Nigel run to their dad, Tom, and start yelling and doing macho actions, in a wideshot you see Charlie walk from the stove, over to the worktop where Henry, Kim and Jessica are making sandwiches and he puts something on a shelf. Then in the following closeup of Nigel and Kyle you can see in the background that he has instantly vanished. (00:07:30)
Continuity mistake: After Mark has been bullied, we see the bullies walk away and do their handshake, but in the very next shot (from a different angle) they do their handshake again. (00:43:35)
Continuity mistake: When they are preparing for Oprah, Kate asks Tom to help with her zipper, Tom says it's stuck. In the next scene when she's coming downstairs you can tell that there is no zipper.
Continuity mistake: At the beginning of the movie, Steve Martin comes into their bedroom after a jog where his wife is proofing her manuscript. There's a pinwheel type of decoration attached to the lamp on top of some family photos in the corner by the window. In the 1st shots, you can even see its shadow on the lamp. Steve says (to Bonnie Hunt) "We could use a little change around here - like this lumpy old mattress." He then moves to the mattress facing her and the photos are still there but the pinwheel thingy is gone. (00:02:15)
Character mistake: In the sequence when Tom is on the phone trying to find a babysitter, he repeatedly says he needs a babysitter for 12 children. However, Charlie, Lorraine and Nora, who does not even live at home, are much too old to need a babysitter. (00:50:45 - 00:51:25)
Continuity mistake: When Bonnie pulls away from her house in the taxi to go to New York, there are no pedestrians on the other side of the street. In the next shot, just a moment later, two people are standing on the previously empty sidewalk facing the departing taxi. (00:43:50)
Continuity mistake: When Nora is on the phone with the whole family trying to get her to babysit, Hank throws his pad of paper on to the table and the shot cuts to Nora. The shot goes back to Hank and he throws the pad of paper on the table again.
Answer: Because he needed a way to coach the team while also watching his kids.