Torches

2

1 or 2, never 3

1, I was taught by the great paulsoaresjr to place torches on the right so when you leave a cave you follow the torches on your left out :D

Hmm left or right but all the way up as high as I can reach

I don’t.

If I'm strip mining then on the right, but in caves it's all over the place lol

Never 3

People who place them like 3 should be shot.

I dig a 3x3 when planning out mining, and place them mirroring each other on the walls, every 7(iirc?) blocks.
.
If it's not planned, then i place them however the hell I feel like.