I will now put forward grounds for why cleaning up unused files and other material from your hard drives can only do your PC good. How fast your PC operates while fetching documents and files from the drive partly hinges upon the number of files stored there. The reason for this behaviour is that the file management core works harder the HDD works harder when a request is received for a file to be retrieved. And as a result of saving files and deleting them, files are no longer contiguous and this impacts file read speed. Additionally keeping private files private is more difficult, the more files you have that you would rather keep secret, the higher the likelihood is that somebody accessing your computer could find and misuse these files. Also removing any excess files will make resources available again that can save you time and effort.