Cache Busting in WordPress
Typical browser caches all CSS and JS files to avoid unneeded download. In WordPress, this has a big effect on your changes to style.css file. These changes will not be immediately visible...
Read, every day, something no one else is reading. Think, every day, something no one else is thinking. Do, every day, something no one else would be silly enough to do. It is bad for the mind to be always part of unanimity.
– Christopher Morley