Duplicate files are inevitable. They continue to occur as long as you use your PC. Although it is not possible to entirely get rid of new duplicates, you can certainly identify and delete the existing ones.
Manually searching for duplicate files may not be feasible approach in a practical scenario. Typically files are divided into different types and scattered across different drives and directories,which makes it difficult to find and compare each file. For example: It is not uncommon to have the same text written over in a Text Document and a Rich Text File. So two files matching same name may not always be duplicates in nature.