Your body replaces your entire skeleton about every 10 years.

Bone remodeling is a lifelong process managed by two types of cells. Osteoclasts dissolve old bone using special acids and enzymes. Then, osteoblasts build a new bone layer in that same spot. This cycle ensures your skeleton stays healthy and mineral-rich.The National Institutes of Health states that adults replace 5% to 10% of their skeleton every year. Different parts of the body change at different speeds. Hard compact bone replaces itself at 4% per year. Spongy bone, found inside the spine and at the ends of long bones, replaces itself at 20% per year.This process also helps control calcium levels in your blood. If your nerves or muscles need calcium, the body breaks down bone to release it. After age 40, the body starts removing bone faster than it can build it. This leads to a slow loss of bone density as people get older.