Why bones are not permanent and have often it is replaced?

Bones are not permanent because they undergo a continuous process of remodeling, involving the resorption of old bone tissue and the formation of new bone. This process is influenced by various factors, including mechanical stress, hormones, and nutrition. Typically, the entire skeleton is replaced approximately every 10 years, although this can vary based on age and health. This dynamic remodeling helps maintain bone strength and adapt to the body's changing needs.