A good rule of thumb is to consider the comfort of your reader. Many readers want to finish a chapter in one sitting. With that said, you must decide what your style is going to be.
Some authors make each scene, no matter how short, a chapter. They will end up with 100 or more chapters in their books, and that is perfectly fine.
Other authors try to set a word-count limit. I personally have found that 2,500 to 3,000 words is a good length, and most scenes seem to average that. One series of my books has longer chapters, as it is really a collection of stories surrounding the main character. In that series, each story forms a chapter and sometime they are longer than 3,000 words.
Within the arc of the entire story are smaller arcs, arcs of conflict and reflection, each created by scenes. The arc of the scene is like any other: it begins, rises to a peak, and ebbs, ending on a slightly higher point of the overall story arc than when it began. Once you have decided what length you are comfortable with for your chapters, longer scenes can be an entire chapter on their own, or several scenes can be chained together to make a chapter.
When you chain scenes together within one chapter, conversations can serve as good transitions that propel the story forward to the next scene. In literary terms, a good conversation is about something we didn’t know and builds toward something we are only beginning to understand.
That is true of every aspect of a scene or chapter—it must reveal something and push the story forward toward something.
With each scene we are also pushing the character arc, raising the stakes a little. Our protagonist grows and is shaped by receiving needed information through action and conversation, followed by reaction and regrouping. This allows the reader to experience the story as the protagonist does, and then to reflect and absorb the information gained before moving on to the next scene.
Some editors suggest you change chapters, no matter how short, when you switch to a different character’s point of view, and this is my preferred choice. I don’t think that is completely necessary in every case, but you should limit point of view changes. It’s easier for the reader to follow the story when they are only in one character’s mind for the majority of the story. If you do switch POV characters, you must change scenes with a hard, visual break such as two blank spaces between paragraphs, to avoid head-hopping. (Head-hopping: first you’re in his head, then you’re in hers, then you’re back in his—it gives the reader “tennis neck.”)
So now we come to a second question: Should I just use numbers, or give the chapter a name?
What is your gut feeling for how you want to construct this book or series? If snappy titles pop up in your mind for each chapter, by all means go for it. Otherwise, numbered chapters are perfectly fine and don’t throw the reader out of the book. One series of my books has numbered chapters, the other has titled chapters.
How do you want your book constructed? You must make the decision as to the right length and end chapters at a logical place. But do end each chapter with a hook that begs the reader to continue on to the next chapter.