iOS is pretty good about nudging you to the next tier as you approach filling your current one, IIRC. When I recently had to jump from 200GB plan to 2TB it was one tap on a notification to move to next tier for my whole family, so even for those of us who can easily afford it's arguably not that sensible a strategy to jump straight to 2TB, unless one's goal is to subsidize Apple as much as you can.

HEVC/H.265 introduced in iOS 11 largely makes shooting 4K on an iOS device cost _roughly_ the same in storage terms as 1080p/H.264 did, so recording in 4K doesn't really move the storage needle here like it used to either, assuming of course you have an iPhone 7 or newer.