Maybe, in a few times, you had updated your CSS and JS files content, but when you tried to accessed the web, the content seemed to be the same before that you commited the changes.
This is due because browsers catches the files and don’t download the new version; they don’t identify that the CSS and JS files content has changed.
To resolve that situation, try a simple trick. Every time you update those files, rename them too (for example, add a numeric value at the end); don’t forget to modify the link to your CSS and JS files in the HTML source code. The browser always will detect the file as a new one (because it’s name has changed), so it will download the file everytime you change it’s name.