This may be because the skills, time and materials required for each job vary depending on different customers' needs.
The materials can vary depending on the desired weight and density.
The materials with which schools were built varied by location and population.
The materials used to create caftans varied according to status and wealth.
The other material varied according to the season and availability.
The materials used in making musical instruments vary greatly by culture and application.
In various areas the materials that are used for traditional medicine vary significantly.
There are many kinds of flute, so the material also varies.
The style and materials used in their constructions vary throughout the city.
The materials used to build villas varied according to what was easily available nearby.