And in the case of "the best (http://officialfan.proboards.com/thread/501420/which-show-survived-cast-changes)", shows that still managed to keep up its quality?

Bewitched-The Darrin switches.
Cheers-Diane to Rebecca change and Coach to Woody change.
M*A*S*H
Night Court

Have to partially disagree with that last opinion. The switch on Bewitched was a disaster. The change from Dick York to Dick Sargent started an immediate downward turn in the ratings, and I now find those episodes unwatchable. MASH probably had the best success of any show with major cast changes. The changes from Henry Blake to Sherman Potter and Frank Burns to Major Winchester took the show in other directions and weren't just more-of-the-same. Although BJ Hunnicutt was a change from Trapper John, I didn't care for that change, simply because Mike Farrell was probably the least-funny actor I've ever seen. I don't remember one genuine laugh I got from him, while Alan Alda kept me in stitches.

Another show that suffered from cast changes was Andy Griffith. When Gomer, Floyd and especially Barney left, their replacements were fair-to-awful. Warren and Emmett were horrible, and Goober could only be taken in small doses. Only Howard Sprague was a good addition.

Bewitched still went on for three seasons with Dick Sargent, and The Andy Griffith Show continued and was successful or it would've ended way before it did.

The Mary Tyler Moore Show was still good after the cast changes (Valerie Harper and Cloris Leachman for Georgia Engel and Betty White)

Newhart - it remained great as it is due to the transition from Leslie & Kirk to Stephanie & Michael

As far as Bewitched---audiences back in the 60's probably didn't warm to the new Darrin, and ratings suffered, but today when I watch the show, I like both Darrins equally and think both did a fine job in the role.
I really don't see any decline in quality of the show after Sargent came along (and he was after all, the first choice of Darrin when the show premiered). The only thing I don't like about the later Bewitched episodes are Elizabeth Montgomery's revealing outfits that were reflecting the emerging sexually open times of the late 60's. Some of her dresses looked like tops that were missing bottoms! You see it on I Dream of Jeannie also. It's just way too revealing even by today's standards IMO.

Back to cast changes that were successful. Without a doubt the addition of Mr. Furley on Three's Company after the Roper's left. I think Don Knotts was one of the best cast replacements in sitcom history.
The character of Mr. Furley was so funny that you didn't even miss the Roper's.

Although I prefer the early years, My Three Sons had a successful cast change. First William Frawley as Bub was replaced by William Demarest as uncle Charley during season five. Then, at the start of season six, Barry Livingston's Ernie replaced Tim Considine's Mike as a son in the Douglas household. And of course, all of the additional women joining the show in later seasons. Because the series was split into two packages for syndication, there seems to be a generation who grew up watching the Uncle Charley/Ernie years and had no clue Bub/Mike even existed. Thankfully, I'm not one of those people. I first watched My Three Sons on Nick at Nite.

Night Court and Cheers are definitely the top two. In both case some of there most popular cast members joined later.
Worst Sabrina The Teenage Witch. Lost Harvey, Valerie The Aunts. All the new characters who joined after college were not good replacements.

Cheers is probably the one of the best examples. I've never watched M*A*S*H, though, but someone born a decade after me would probably say the same about Cheers.

With Three's Company, opinion is polarized with Suzanne Somers, and its hard to separate her removal and show's direction from then out of the other cast change, which was the landlord, from The Ropers to Mr. Furley change.

I liked the major season 2 cast changes on shows like Facts of Life, and A Different World, but didn't like the last season of ADW.

More recently, Parks and Recreation survived well after Paul Schneider left the after the second season. Adam Scott and Rob Lowe joined the show and replaced his role, and Retta got an increased role. I think the show improved overall, but it lost steam after season 5.

I prefer the earlier seasons of The Office, even before the cast additions of Ed Helms, and Ellie Kemper, although many liked those cast additions but just didn't like the very end of the show after Steve Carell left.

With Three's Company, opinion is polarized with Suzanne Somers, and its hard to separate her removal and show's direction from then out of the other cast change, which was the landlord, from The Ropers to Mr. Furley change.

I disagree because Mr. Furley arrived a full season before Suzanne Somers was given the boot. So the direction had already began to shift well before she left and by that time, Mr. Furley was already an established character. So I don't think there should be any issue with separating his addition to her departure.

With Cindy & Terri however, I can agree with your assessment, because they came after she was gone.

I didn't like the Cast Purge after Season One on The Facts of Life, and missed Marisa Tomei and Lisa Bonet on A Different World. I also didn't care for the recast on Bewitched, or Hesseman leaving Head of the Class.

Cheers is, IMO, one of the few shows that successfully transitioned past one of the leads leaving the show. The Rebecca years were nearly as good as the Diane years.

Cheers is probably the one of the best examples. I've never watched M*A*S*H, though, but someone born a decade after me would probably say the same about Cheers.

With Three's Company, opinion is polarized with Suzanne Somers, and its hard to separate her removal and show's direction from then out of the other cast change, which was the landlord, from The Ropers to Mr. Furley change.

No, I don't think opinion was ever polarized. I remember watching the show in first run, and I don't ever remember anyone feeling that Somers was a huge loss (or made a dent), because everyone watched for John Ritter, not anyone else.

Cheers, MASH, and Three’s Company continued to be successful in the ratings - and arguably creatively - after their cast changes. Bewitched survived but with reduced ratings, and creatively it was spent; I’m not sure that was entirely due to Dick Sargent. Andy Griffith continued for a few years without Don Knotts, but those episodes are rerun far less than the classic years of the show. The Facts of Life was successfully retooled for its second season after an unsuccessful first season, but I consider that a different scenario from the others, which were long-running successful series when they had to endure major cast changes.

I didn't like the Cast Purge after Season One on The Facts of Life, and missed Marisa Tomei and Lisa Bonet on A Different World. I also didn't care for the recast on Bewitched, or Hesseman leaving Head of the Class.

Cheers is, IMO, one of the few shows that successfully transitioned past one of the leads leaving the show. The Rebecca years were nearly as good as the Diane years.

I'll have to disagree about The Facts Of Life. I think what they did dropping all of those characters after the first season was a good thing. There were simply too many characters for a half hour sitcom, people usually can only focus on and care about a handful of characters to be interested in a show like that.

Ed.

I'll have to disagree about The Facts Of Life. I think what they did dropping all of those characters after the first season was a good thing. There were simply too many characters for a half hour sitcom, people usually can only focus on and care about a handful of characters to be interested in a show like that.


The "too many characters for a half-hour sitcom" cliché has been disproved, repeatedly. Audiences like having a larger number of students. That's why Saved by the Bell had six students and Head of the Class had more than ten. A show with only four students limits itself on the types of stories it can tell.