Sometimes shows want to or need to move characters around. Whether it’s students graduating or people moving. But not wanting to fire actors and replace characters, the people behind the shows have to make stretches in logic to keep characters together. Here are a few examples. Please add your own.

The Facts of Life During the first four seasons, Blair, Natalie, Tootie (and beginning in season two) Jo went to Eastland. Mrs. Garrett went from being their housemother to the school dietician. After Blair and Jo graduated, however, this presented a problem. How do you keep the characters together for season five? Simple, Mrs. Garrett opened her own business, Edna’s Edibles, and hired the girls, who also lived together. More changes took place as the series went on but this was the big one in keeping everyone together.

I Love Lucy During the show’s final season, the Ricardos moved to a house in the country. To avoid a cast change and replacing the Mertzes, Ricky hires them to help with the farming, so Fred and Ethel move into the Ricardo’s guest house.

Boy Meets World The first stretch came in season two. Mr. Feeny had been Cory, Shawn and Topanga’s sixth grade teacher. However, the students would be going to a different school in the second season, John Adams High. Mr. Feeny changed schools with the kids and became their principal and continued as their teacher. Then an even bigger stretch occurred in season six. After Mr. Feeny retired and the kids grew up and went to college, he soon found himself as a fellow student for a few days. He so impressed Dean Bolander, that he was hired on as a teacher and was able to teach Cory and the gang for two more seasons when the show ended its seven season run.

Laverne & Shirley When the producers wanted to change the setting for this sitcom in its sixth season from Milwaukee to Hollywood, California, not only did Laverne and Shirley make the move but so did Laverne’s father, his new wife, Lenny, Squiggy and Carmine. In other words, the whole cast. Since it was set up that Laverne’s father had moved their first, it was reasonable for the girls to visit him and then decide to stay but ridiculous to think of Lenny, Squiggy and Carmine also moving there.

The Lucy Show In another Hollywood move, Lucy went to live in California at the beginning of the fourth season. To her surprise, her friend, foil and banker, Mr. Mooney had already moved there and the two would remain together for the rest of the run (and as different characters in her next series “Here’s Lucy”).

Community At the end of the fourth season, Jeff graduated early but the rest of the study group was set to graduate at the end of the school year. It was only a half-season, so the audience didn’t get to make it to the graduation for the rest of the class. When the series came back for its fifth season, in order to keep the characters together and still be set in Greendale Community College, Jeff returned as a teacher and the others (minus Chevy Chase’s Pierce) reenrolled.

Full House During the show’s fourth season, Uncle Jessie married Rebecca Donaldson. But instead of moving out of the house, he and his new bride moved into the attic of the Tanner house simply because Michelle would miss him too much. Even as a kid, I thought this was a dumb plot device to keep him in the house.

What are some others you can think of?

Boy Meets World The first stretch came in season two. Mr. Feeny had been Cory, Shawn and Topanga’s sixth grade teacher. However, the students would be going to a different school in the second season, John Adams High. Mr. Feeny changed schools with the kids and became their principal and continued as their teacher. Then an even bigger stretch occurred in season six. After Mr. Feeny retired and the kids grew up and went to college, he soon found himself as a fellow student for a few days. He so impressed Dean Bolander, that he was hired on as a teacher and was able to teach Cory and the gang for two more seasons when the show ended its seven season run.
I just hated that stupid idea, wouldnt Cory and his friends start to ask themselves why Feeny is always intruding in their lives? I know BMW has it's share of fans who were kids then and adults now but I couldn't take the dumbness it was turning into.
Full House During the show’s fourth season, Uncle Jessie married Rebecca Donaldson. But instead of moving out of the house, he and his new bride moved into the attic of the Tanner house simply because Michelle would miss him too much. Even as a kid, I thought this was a dumb plot device to keep him in the house.

Yeah what a stupid idea, and here is when you would cue to audience to go "awwww", to which I say a big F-U.

Here's another, on Beverly Hills 90210, Brandon, Brenda and their friends start the series in their Junior year of high school but the producers wanted the whole cast to stay in high school awhile longer so they don't become Seniors finally until the 3rd season.