Change is inevitable even on hit TV series.
Sometimes actors get bored or leave for personal reasons.
Other times, producers and writers get tired of actors and find a ratings-grabbing manner in which to get rid of them.
Some series, such as M*A*S*H or Grey's Anatomy or Law & Order, make cast changes seamlessly seemingly for decades.
Still, an essential actor can leave and his or her character gets written out, and the series falls apart. Everyone has one of those (how could Sleepy Hollow have continued without Abbie?).
Sure, many shows shuffle their lineups in their first or second seasons, until they find their mojo. Does anyone remember Agent Vivian Blackadder (great name for a BBC character) on the JAG episodes which introduced NCIS?
The photos below look at good and bad transitions on long-running network series.
Comment below with your best and worst casting changes.
Chin and Kono - Hawaii Five-0
With its original lineup, Hawaii Five-0 had more of a family feel. That started with protective Chin and his younger cousin, Kono. He, McGarrett and Danny were bickering brothers, and Kono the younger sister. But things had to evolve with the contract-driven departures of Daniel Dae Kim and Grace Park.
Tani and Junior - Hawaii Five-0
The departures of Chin and Kono for jobs on the mainland left the Five-0 task force short-handed. Enter Tani, a Police Academy dropout, and Junior, like McGarrett a former Navy SEAL. Unlike their predecessors, they're rookies learning from scratch. They seem like work buddies now, but might they be something more in the future?
Hetty Lange - NCIS: Los Angeles
Then there's the wrong way to handle changes. For eight seasons, Hetty has been the best of the NCIS directors. She's like one of those Russian nesting dolls, the little doll inside wrapped in layers of secrets. She's been the Yoda for the Los Angeles unit. But she's spent NCIS: Los Angeles Season 9 trapped in Vietnam. Whether that's Linda Hunt's choice or the writers' idea, it's hurt the series.
Shay Mosley - NCIS: Los Angeles
That's because Hetty has been replaced, hopefully temporary, by Mosley, a caricature of the heartless bureaucrat. She's come to Los Angeles to correct all the agents' bad habits. All that's needed is the Wicked Witch theme and some flying monkeys whenever she comes on screen. There's been some feeble attempts to humanize her, which have failed. I feel badly for Hidoko, who is seen as guilty by association. Time to rescue Hetty!
Jason Gideon - Criminal Minds
Gideon set the tone for this series about the profilers of the Behaviorial Analysis Unit. Rejoining the unit after medical leave for PTSD, he was always on edge and could too easily get into the mindset of the unsubs they hunted. When Mandy Patinkin left after two seasons, later saying it was destructive to his soul, it was easy to sell Gideon departing because of emotional issues caused by his girlfriend's death.
David Rossi - Criminal Minds
When the time came to replace Gideon, who better than Rossi, his former partner and best friend? Rossi came back from early retirement, leaving behind lecture and book tours to take care of unspecified unfinished business. While Rossi has his demons, he just doesn't seem as tightly wound as Gideon. He has a life outside the BAU, and seems like everyone's fun uncle.