Gravel may require periodic break up and removal of hard pan. Low initial cost. Ease of installation. Does not pulverize. Not ideal for microbial growth.
Materials are readily available.
Not susceptible to vandalism except by contamination. Gravel is less attractive to animals than sand. With normal use, combines with dirt and other foreign materials. Depth may be reduced due to displacement by children's activities and sand may be blown by wind. May be swallowed.