You don’t need to. The charge level just keeps climbing each day. It’s not like it resets to zero at midnight or something. So it will get to 300 or 400 (Model S) if you let it.

And most people living near a city aren’t 150 miles away… more like 5-10 miles away. Even 60 miles away, there’s no need to charge to 300. Except for special cases, and on those rare times you supercharge for maybe 10-15 minutes to augment it, while watching Netflix or posting on Hacker News on the screen. Let me know if you have any more questions, always happy to clear up these misconceptions!