I support multiple macs in my home, so I like to keep software on a network share. This is done mainly because I have a limited quota (110GB/per month), however my home network will almost always be faster than the Internet.
What really annoys me is applications that downloads additional system resources, such as updates and plugins and then provides no way to back up said resources.
One of the most annoying is the iOS compatibility update for GarageBand, this update is not in Software Update or on Apple’s Support Downloads Page.
Using Wireshark, I was able to find the download source, which results in a .pkg file, a OS X Software Package file. This should work for any mac, however Apple may change the location of the file in the future.
What would be better if Apple makes this update accessible via their Support Downloads page, but I wouldn’t hold out for that.