Lion was the first version of OS X to be made available in the App Store, and it made sense that Mountain Lion would follow suit. While this method of software distribution is handy, it does mean having to have access to the internet and this is not always an option. Thankfully, it is possible to create a bootable USB driver installer for the OS.
There are numerous advantages to going down this route. If you have more than one computer on which you would like to install the operating system there is no need to wait for ages while the software is downloaded multiple times, and it also means that you can avoid exceeding any monthly download limited your ISP may have put in place.
It is possible to create your USB installer using OS X’s built in Disk Utility, but Lion DiskMaker is, as the name implies, a handy tool that helps to automate and simplify the process. All that you need to have to hand is an 8GB drive that you don’t mind formatting and the software will take care of the rest for you.
To save you from having to download Mountain Lion more than once, it is important that you run this tool immediately after you have downloaded the IS from the App Store – do not wait until after you have perform the upgrade or the installer will be deleted.