Is L always changing?

[meme]

I always say that L is processing around Lz, never line up with Lz, so is that means L is always change its direction and so L vector is changing? So what force is changing it?

[mathman]

In order for questions to get answered, they have to have some minimum level of clarity. At least tell us what you have in mind for "L" and "Lz".

[meme]

To me, L mean angular monmentum, which is R X P, R is position vector, P is momentum vector.
Lz is the direction which L is processing around.

[mathman]

It is not clear to me what motion is being described? Is something going around in a circle or is it something else?