For novels, I limit my chapters to about 2 Word Doc pages. I heard before that novels with compact chapters like that are more likely to be promoted on Tapas, since readers want stories they can easily get caught up on in 10 minutes or so. And to be honest, my chapters usually wrap up in 2 pages or less all on their own.
For comics...I have no idea. I write them like I write novel chapters: they end when they end. But how that will translate into panels and pages, not even I can foresee. Sometimes I add stuff in and cut stuff out even while drawing; my editing process is an unholy mess. XD