Let's say there's an url, let's call it
This location has directory listing enabled, therefore I can do this:
wget -r -np http://www.some-url.com/folder/
To download all its contents with all the files and subfolders and their files.
Now, what should I do if I want to repeat this process again, a month later, and I don't want to download everything again, only add new/changed files?