I follow an outline and keep chapters to a minimum, but break now and then within a chapter at a change of something fundamental. If you like Proust, which I gather you are not used to yet, chapters will tend to be entire novels in themselves and it is all first person in one character. If you like C P Snow each shapter will be a definite scene with particular characters doing one specific thing and one character traipsing through the whole thing. If you like somewhat popular novelists such as Graham Greene there will be chapters but they are often irrelevant since he tells a story from beginning to end.
Breaks are up to the author and can be for any purpose but should be consistent: change of characters, change of scene, change of day, change of something.
I am really just trying to start a "writing" conversation in hopes the thread and club does not die.
I do find an 81 page chapter extraordinary though and thought it might be a good subject to get some writing tips.
If the tip is just hit page break when you feel you have written enough - then perhaps I should be more selective in the next topic I chose. :>)