My experience is that all my code gets thrown away or rewritten at some point. I've seen what code that doesn't get rewritten looks like; I'm intent on never inflicting anything like that on the world.

As far as types go, I've found that types actually help more during prototyping than later on. (At least for code I've written myself; types are great for helping me navigate other people's long-term codebases!)

Types give me a way to sketch out and iterate on an overall design without needing to implement anywhere near all the logic I'd need; then, when I start in on the logic, it naturally lays down on the skeleton the types provide. Compared to my experience with Python—where I still use some types!—I've found it easier to start and quickly try different designs in Haskell.