Some of the hurdles you've faced as your book was nearing its ending...

[Xcalibur_Xc]

Did you end your book where it was supposed to end?
OR
Did you ditch the idea of ending it where it was supposed to end and, instead, decide to write another arc, continuing the story?

 

[wresch]

I have one series that is 8 books long. I would finish one and immediately have an idea for another arc. I think I rounded everything up and finally came to a conclusion in book 8, but there are still times when I think of writing #9. I think that comes from loving the characters and places. If so, why should I stop writing about them?

My recommendation to you - finish your current book but be open to a series. If the character will sustain it, just keep going.

 

[ParticleOfSand]

I'm super ambitious and decided to go for a really long book. There's a higher chance I get burnt out before I reach my planned ending.

 

[K5Rakitan]

I decided to write another arc, and then I got pregnant.

 

[QuercusMalus]

Did I address these plot points sufficiently? Did I foreshadow this event enough, too much? Did I leave any gaping plot holes? Does the progression make sense? Is there too much deux ex machina and asspullitis? Do I have enough material for another story or should I just extend this one out?
The questions never stop, and changing one thing leads to the changing of five more.