Pearl and bead restringing prevents your necklaces from breaking at inopportune moments with regular string replacements. Pearl necklaces are strung on silk or nylon thread that is knotted in between each pearl. This thread is exposed to dirt and grease that causes it to deteriorate over time. If you wear your pearls often, consider restringing every two years; otherwise, every five years is recommended for general maintenance, durability, and security.