I need to know how to get a bootable flash drive for my backup OSX software. Help please. Apple is useless, as usual.

To keep my systems working at top speed, I do not store any data on my main drives, only software. Data I store on a separate drive and its copy drive. The computer only handles the data for the specific project I am working on and then it is removed and stored on the data storage drive. And as a matter of maintenence I like to reinstall my operating system and software periodically. As a matter of emergency I understand there is a way to download the recovery disk assistant in advance of a disaster on to a flash drive and boot up a dead system and reinstall the OS from the flash drive on which the operating system is stored. I understand that the versions of my OSX consume more than 4GB and so I was planning to purchase 1 8GB flash drive for each system. It is rumored that some flash drives are bootable or that you can make them bootable somehow. That is my question: what kind of flash drive do you buy and/or how do you do it? Flash drive companies are being non-commital and will not tell me anything. Yet I remain under the impression that IT guys do indeed exist who go around with bootable flash drives to start up people's computers and I want to provide for myself this convenience. Do you know how this is done?