Marimo balls are regarded as good luck charms in Japan, and since they have been known to live to 200 years and beyond, they are often kept as family heirlooms. They are thought to symbolize close bonds between family members or close-knit friends, and are often passed down to children and grandchildren or nieces and nephews. By the time future generations receive the marimo balls, they will be larger in size and will continue to grow with each generation. Additionally, marimo balls are sometimes given to young children as "pets," since the only care they require is occasional water changes. Marimo balls are also thought to represent everlasting love; thus, they are often used as wedding table ornaments or even gifted at weddings. They are appropriate as a gift to the bride and groom, and smaller marimo balls make wonderful take-home gifts for the guests that will serve as mementos of the newly-weds' special day.