In my experience, writing the end of a novel has to be the hardest part. (Or, at least, the second hardest part.)

Sure, knowing where to start can be problematic. Do you go with the proverbial “day that’s different”? Should the protagonist’s pertinent backstory frame the front end of the piece or be peppered throughout the narrative? Or both?

I’m sure most writers have more than a few false starts stashed on their hard drives. The good news about bad beginnings is they tend to fizzle out suddenly and for the most part painlessly. No harm, no foul. Nothing to see here. Move along to the next idea…

Of course, once you have a story that sticks, figuring out what should happen between the introduction and the resolution is no picnic either. Too many details and deviations kill the pacing, but if you skimp on subplots and layers, your Great American Novel devolves into the awkward middle child sandwiched between long short story and a novella.

Sometimes you lose steam or wander far afield from where you thought you were headed. The journey itself can be exciting, and when obstacles present themselves, you find a way to write around them. Worst case scenario, you’ll tidy and tighten during the editing process.

But endings are the worst! You wrote a beginning that promised to be worthy of your time and talents, something strong enough to support the string of chapters that follow. If you used an outline, you always knew where the finish line lay. Even if your plot has meandered a bit, had a good idea where your characters are going to end up by the final page.

Then again, maybe not.

It’s easy to start second guessing as the epilogue draws closer. You’ve spent chapter after chapter building up to this moment. Is the climax big enough? Does the dénouement drag on too long? Will the final sentence leave the reader with a sense of satisfaction or indifference?

The longer the novel, the more problematic those final decisions become. A trilogy or longer saga raises the bar even higher, which might be one of the reasons why some authors choose to continue their epics indefinitely. (The “never-ending story” phenomenon is a topic for another day.)

Yet when to call it quits and how to wrap it all up are irrevocably intertwined. I’m reminded of this while watching commercials promoting the final season of three different TV series: 30 Rock, Fringe, and The Office.

Only time will tell whether the respective finales will flourish or fizzle. But going into the home stretch, I approach each of them with very different expectations, and I believe there is something any writer of fiction can learn from the treatment of television endings.

In the case of The Office, I had already given up on the series, watching only a handful of episodes after the departure of show staple Michael Scott. In my opinion, the series should have ended when actor Steve Carell walked. My guess is that the network was hoping to squeeze a few more miles (and dollars) out of the mockumentary, and when profits didn’t look promising, they gave the once-successful show a chance to say goodbye as a mark of respect rather than unceremoniously canceling it.

I’m sure there are still plenty of people who want to say a proper farewell to Jim, Pam, Dwight, and the rest of the gang.

While The Office has been in decline, Fringe has weathered ups and downs, including (again, in my opinion) a ho-hum start. My interest in this sci-fi rollercoaster follows a bell curve, and the most recent attempt to “restart” the story—an all-to-common occurrence thanks to parallel universes and alternate timelines—have left me wondering whether I can really care about characters when I’m no longer certain of their origins.

I might have stopped watching Fringe altogether this season if I didn’t know the end was near. As it is, I’ll stay tuned simply to see whether the show can redeem itself as the clock winds down. Any ending is better than none, I suppose.

30 Rock, on the other hand, has kept the laughs coming for six straight seasons, and I have no doubt that the seventh will leave me in stitches. From my perspective, the show is going out on a high note, not so unlike a past NBC hit by the name of Seinfeld. There’s something to be said for going out on a high note, and even though Seinfeld’s finale proved divisive (I personally thought it was genius), no one can argue that the writers and cast left on their own terms and with their high standards intact.

So how can a writer—whether a screenwriter or a novelist—know when to say when? Is it better to leave the audience wanting more or to wrap everything up with a neat little bow? Does the book deserve a sequel, or are you better off saying what you need to say in a single volume?

Obviously, there’s no one right answer to these questions.  Instinct, artistic integrity, trusted opinions, and trial and error—all of these things (and likely more) weigh into the decision.

For good or for ill, every author must choose where the story concludes and when to type those two final, fateful little words.