All the time and all the way up, the only time I have it off is if someone is watching me play.

Most of the time. However, if I take my contacts out or don't wear my glasses then I turn it off since the 3D effect doesn't work with shitty eye sight. So probably around 70-75% of the time I have it on.

I always put it on. Not all the way, but maybe about 3/4. Depends on the game, too.

I normally play at full 3D in single-player games. When playing multiplayer, I find the 3D distracting, so I turn it off.

The only time i ever have it off is when i am playing it on the Bus, the movement of transport coupled with the 3D does not have a good effect on me lol.
Apart from that...ALLLLLL 3D ALLLLL THE TIME!

3d , all the time it makes the games look less jagged and the screen bigger, what's not to like :)(

I always have it on and set to max, except for games with really intense 3D (MGS3D and Pilotwings). I think I'm one of the few people who like 3D.

Mostly on and mostly at full
plus i must say 3D was a big selling point for me and still wows me to this day as much as the first

Only when I am playing starfox

Pretty much never. It's a shame because I really want to like the 3D but I just can't. Still love the 3DS though, and am glad others like it guess, I just don't care for the feature.