Perhaps the hardest question for a sitcom star to answer is when to move on and do something else.
And the decisions that various sitcom stars have made can be argued about. Maybe Dick Van Dyke should have done a year or two more of "The Dick Van Dyke Show." Maybe Mary Tyler Moore should have done a couple more seasons of "The Mary Tyler Moore Show."But, on the other hand, maybe if they'd stuck around they would have ended up like Roseanne, who definitely did one year too many of "Roseanne" - a show that turned into utter dreck in its final season.
The fact is that stars - as well as co-stars, writers, producers, crews and network executives - get comfortable. A show becomes a well-oiled machine, churning out lucrative episodes.
Such was the case with "Murphy Brown" and its star, Candice Bergen. She has mulled over ending the series for several years now and has announced that this is absolutely, positively the last season for the show.
"Maybe there should be some sort of tacit rule that sitcoms shouldn't exceed their life span," she said in a recent interview. "But how do you decide what their life span is?"
Like everyone else, she said, she would wish that "Murphy Brown" could end while it's at the top of its game.
"But if we went out when we were strong we would have gone out (after) our fourth year," Bergen said.
And she can easily make a case for that. Series creator Diane English left at the end of the fourth season - just after Murphy gave birth to her baby - and the show floundered after that.
"It was a very rocky transition because they sort of had a bombshell to deal with the baby and Dan Quayle," Bergen said. "It was sort of like - oh, we're left with this baby, now what do we do with it?
"In the sixth year they sort of brought it back, but by then people were sort of fed up. And then the show got terribly broad in the seventh year. We had wonderful producers in the last couple of years but they tended to write more for comedy rather than for character. The emotional core of the show really left with Diane."
This, the 10th and final season of "Murphy Brown," is proving just how important English is to the show. She's back as an executive consultant, and the show has recaptured most of its old magic.
It's funny. It's heartfelt. It's watchable. It's topical.
It was English's idea to have Murphy deal with breast cancer, and it has been a master stroke. The plot device has not exploited the issue but has instead used it sensitively.
And English, along with new executive producer Marcus Flanagan, have proven just how far afield the show had gone. When Lily Tomlin came aboard last season, her character was not only unlikable but was also not funny. This season, Tomlin is being used perfectly - she's not overused, but she's a scream when she's on screen.
The same could be said of Murphy's son, Avery - a character who has been mostly ignored for the past five years. He's now part of Murphy's life and half of what's turning out to be a pretty good buddy comedy team.
Tonight's episode of "Murphy Brown" (7:30 p.m., Ch. 2) clearly demonstrates how far back the show has come. Jim Dial (Charles Kimbrough) has had trouble dealing with Murphy ever since she learned she had cancer. Now that she's in the midst of chemotherapy - and very sick because of it - Jim feels he has to do something.
So the uptight, strait-laced anchorman goes out and buys Murphy some marijuana in the hopes that it will quell her nausea. (Jim, of course, warns the dealer that he's a "comparison shopper.")
The show doesn't glorify drug use, but it does come down clearly on the side of allowing cancer patients to use marijuana to help them survive treatment.
It is a hoot to see Jim grow indignant when he learns his purchase is full of stems and seeds. "You pay good money for grass and this is what you get!" he exclaims.
It's also touching and heartfelt as Jim finally expresses his feelings for Murphy. It's the combination of humor and pathos that only the best sitcoms can pull off.
Bergen and the rest of the "Murphy Brown" cast are "savoring every week" - particularly because they have "scripts of such a high quality."
"If the scripts were not coming in the way they are, I think all of us might be thinking, `Oh, geez, what have we done?' " Bergen said. "But the fact that the scripts are really stunning and smart and at the political edge and the really very sharp humor that Murphy used to stand for, sort of makes all of us proud that we have done a 10th year."
And Bergen and the other cast members "love working together. We love doing the show. . . . I think there's a real consciousness that every week is the last October we'll do, the last November we'll do, and that we're building toward the end of an incredible run - an incredible streak of luck."
And for longtime fans of the show, this final season is a well-deserved reward.