Topic: How sturdy Is the 3DS?

Well my 3DS has had its fair share falls, I dropped it from a car onto pavement, fell off my bed onto carpet (my bed is a few feet off the floor) been sat on by a few careless people, and has got wet from rain.
Still works like new only scratches on the outside that are hardly noticeable.

From my experience, it's a mini tank.

I've dropped mine twice before once on wooden floor and once outside on concrete and worst damage was scratches so id say pretty durable

You'll lose a lot of paint off your L and R buttons (as well as rounding them off) but nothing more than that.
Provided the lid is closed when you drop it (even if it opens when it hits the ground) it'll be fine. I think it may be possible under enough damage for the spring-load in the cartridge slot to break, but that doesn't really affect much.