If I buy a 3DS, does the 3D function stay on constantly, or can I turn it off?

Yes, you can turn it off (or even lower the intensity)

The 3DS has a slider on the top screen, which you move up and down. All the way up is maximum 3D, while the very bottom is No 3D at all.

So you can even just have slight 3D.

There is a function to turn it off. Here is how to do it.

1. Turn it on

2. Go on system settings

3.Go on fouurth option on bottom screen

4 choose restrict or dont restrict

5. Then tap ok

Here is the website so you can check out the rest of the tutoriL

http://ds.about.com/od/nintendods101/ht/How-To-Dis...

Nope you can turn it off. There is switch by the top right side of the screen to fix up the level of 3D to what fit you so yeah can be turn off.

Yes u can but I would suggest a intendo ds lite (very first 1 that came)

there's a slider that lets you control the 3d perception. you can play in 2d if you like.

You can turn it off

you can switch it on and off