I'm going to be totally unhelpful & say it depends. Ive just finished a mystery novel that doesnt have chapters -- it's got four main 'sections' of varying lengths, & breaks denoted by three asterisks * * * at the end of each day. Some days are half a page, others run for fifteen.
That seems to work OK. I hadnt planned it like this at all, in fact I started it off with chapters but it didnt work.
On the other hand, with the non-fiction travelogue I'm working on at the moment, I'm trying to have chapters of roughly even length, around 1500 - 2000 words, but that isnt always working.
I think it's best, if you have chapters, to have them of roughlybut not unbendingly similar length; & most importantly, as someone else has already said, make each chapter a kinda organic unit of its own, with a natural finishing point. Or cliffhanger, of course.
Having said that, sometimes if you can't find the natural 'perforation line', it can work suprisingly well,simply to do it numerically: Put in a chapter break every 2000 or 3000 words or so and see how that goes.
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Play with it & see how it goes, but dont get too hung up about it now.
