I save my .dmgs in a folder. Inside that folder I have sub-folders for Apps, Utilities, Internet, etc. If the .dmg name isn't specific enough, or doesn't contain the version number, I'll make a folder with the software name and version number and put the .dmg in it. Usually I'll keep 2 versions of software .dmgs (at least short term) in case I have to go back to a previous version. For those that think you can always download it again if you need it, most of the time that's true, but sometimes, especially with less popular shareware/donationware/freeware it can hard if not impossible to find a source.