Q: CSS and JS fail when upgrade made to Drupal site I've run into an issue that crops up when I make a change to a Drupal site - www.productworld.com
This is how the problem crops up:


*

*Make a change to site, e.g. add javascript tracking code or adding a new static webpage.

*When NOT logged in as admin (viewing the site as a regular visitor), the homepage is now screwed up. It appears that the CSS and JavaScript for the homepage aren't loaded. When logged in as an admin, I see a cached version of the site, looking as it should. I use two separate browsers to confirm the problem - one where I'm logged in as Drupal admin in Chrome, and two where I view the site in Firefox as a non-logged in site visitor.
Here's some screenshots of what the site looks like when the problem crops up:
http://imgur.com/xs3hF
http://imgur.com/wMBVq
http://imgur.com/Gksb9
http://imgur.com/eZPTE
Note: the company images that you see (iWatt, Roal, Assa Abloy etc) should be in a nodequeue (a jQuery image slideshow), but instead they appear one after the other. The blue box with the gold call to action appears way down the page. This is what leads me to believe that the CSS and JS isn't loading. 
3.Clearing the Drupal cache fixes the issue.
It's obviously highly undesirable to have a site that gets screwed up everytime a simple change is made to it. 
If anyone has run into a similar issue, please let me know. 
Thanks.

A: When you make changes to the site with caching enabled it will cause problems. This is because it will be using some cached copies of earlier files.
I tend to make changes to a development version of the site, then roll them out to the live site and clear the cache.
