How is that not just how you should do everything? Finish what you start before you jump to the next shiny thing. It's a basic rule that keeps your whole life from being a mess of half done stuff.
You actually fill every page no matter what? That's wild. Once I spilled coffee on my notebook and the last few pages were stuck together. Forcing myself to use them would have ruined my notes. Sometimes a fresh start is just better. Sticking to a rule like that makes no sense when life gets messy. What if you need a new section for a different idea halfway through?