I only modify them through AdminCP. For instance, I have modified the header template, to add my logo and banner system. I'm not getting any errors. I just wondered, when I make a change to the template code, it is on the server but not on my hard drive. If I needed to upload the files again, if there was a server meltdown or someone hacking the files, that I'd have to redo all my code changes by hand, would I not? So I thought that if I backed up my files on the server, I would have my butt covered.