Timing in animation

In animation timing is one of the key principles.And any error in timing may cause a huge disaster to your overall animation .

In tradition animation the key frames are drawn in two , where for 24 frames , the 12 frames is been drawn ,And is projected in two's.

but now in production , limited animation is used widely to reduce the production cost .where 6 to 8 frames are drawn and  projected  in two's,That makes the total 12 frames, the half of traditional animation timing .