2013 Toyota Prius — hybrid fuel economy dropped with no warning light

Owner notes beat generic advice here. On the 2013 Toyota Prius in Austin, I'd fix the thing you'll notice every day before chasing spec-sheet extras. That's where I'd start. On “hybrid fuel economy dropped with no warning,” that was the fork that mattered for me. Write the result down so the next test isn't a repeat of the last one. I'd rather look cautious in this thread than stuck later.

I'd keep this practical. Verify the cheap/easy branch on the 2013 Toyota Prius before a big repair or a big spend. Then you'll know the next fork. Write the result down so the next test isn't a repeat of the last one. This is me being the wet blanket on purpose.