For me, it's a bidet toilet seat. I bought one that didn't really fit as well as I hoped, so now I am shopping for a v2 based on experience. I don't want to live without one going forward. That's for sure.
To add to this, there’s nice multi function ones. I have the Black and Decker Matrix drill (cordless and corded) with several attachments. I don’t do a ton of maintenance nor professional projects and it’s been a huge life (and storage) saver. Super convenient.