Cells divide for a number of reasons: 

• To produce new cells from older cells 
• To provide more cells as necessary for growth, development, and survival of a living organism
• To create new skin cells in order to repair or renew damaged skin cells and heal injuries such as bruised skin 
• To maintain the total number of chromosomes
• To regulate the shape, size, and structure of an individual

Cell division is key to the growth, repair, and reproduction of cells, which is crucial in all living organisms. Without this vital process, no species would be able to grow or reproduce.