I set my Kindle to show me how much time left I have in the chapter. I also watch the percentage through the book but I monitor the time left in the chapter more closely.
I think the best system I've seen for this is in the Moon+ app. It shows the number of pages in the chapter and the number of pages I've read. In this case pages are defined as screens full of text so it's a good indication of what I'm doing and where I am that's related to the way I'm actually reading. It also gives a percentage in the book.
Oh how I wish I had an e-ink Kindle that let me use Moon+.
Barry