Used Twice, for instance, we may have put the blog background color twice and doesn't noticed it.
Overlapped , i.e. many different values for one styling property, such as 2 different designs for the body background. on this scenario the browser will only shoose out one design, making the other useless.
Unused. You may have added a beautiful widget and added custom stylesheet for it. But then later decided to change it for a new one or delete it entirely. The style sheet for this widget still remains behind, no longer in use.
How to clean unused stylesheets?
More than just these redundant css may add to your host file size and loading time of your website it also affects how the site performs because of needing to process the extra styling codes.
A well known browser extension, tagged as Dust Me is used for just such a purpose. It searches your site pages, and lists all the overlapping and redundant styling sheet rules. Other browsers like Firefox and Opera users will need to add this plugin, and fortunately for its users, Google Chrome have is own built-in developer options in which you can use to clean redundant CSS.