I was asked the other day whether or not it was a good thing to crack your back, neck, knuckles, etc.
I chose to answer the question this way:
Cracking you back,neck,knuckles....whatever...is not necessarily bad. My knees crack in the mornings, sometimes my back cracks when I twist.....I don't pay very much attention to those sounds. However, when I'm out and about, I pay very close attention to any cracking sound. If I'm ever standing on something and I hear a crack I move. Mortars in Iraq landed with a CRACK. If you are ever walking on ice and you hear a crack. my advice would be to take heed and run like hell.
I have since tried to think of a cracking sound in nature that didn't cause me to take heed. I couldn't think of any.
In summation, I don't worry if parts of my body sometimes crack, but I wouldn't go out of my way to try to make it happen.