To avoid duplication of effort and wasted time and resources, it is essential that such information is available.为避免人力的重复以及时间和资源的浪费, 必须向人们提供这类信息。

unnecessary duplication of resources不必要的资源重复

Some are exact duplications of items on display in the museums.有些是和博物馆的展品一模一样的复制品。