Do I need the .dmg's?

Always wondered, once I've installed a piece of software eg: firefox, do I need to keep the .dmg file or will it stop working if not? Just thinking of conserving dspace but I presume they need to be keep in order to function properly?

Nope, once you've dragged the contents of the .dmg over to your Applications folder you can eject and trash the .dmg. Perhaps make sure it runs before emptying the trash if you're real paranoid, but usually you don't need it.

You do not need to keep the .dmg after you have installed the app. They can be tossed without issue. Particularly if it is a drag and drop app.

If it is one of those apps that come with their own installer and uninstaller, you can toss the .dmg if the uninstaller is also installed. If the uninstaller, remains as a part of the .dmg, then I would suggest keeping it.

Next we'll get someone saying they tossed the .dmg and their program disappeared. Well, that's because you didn't install the app. After you open that .dmg, you need to drag and drop the app's icon into your Application folder. Now it's installed and now you can delete the .dmg.

I have a folder set aside of DMGs just incase I screwup and need a reinstall (it happens),that way I don't need to hunt them down at different sites

I'm with iNAP, I collect all of the DMGs I download. It's also useful to have older versions around in case the author decides to start charging for his/her software, such as Senuti.

With so many updates to software and today's high ADSL internet/cable speeds, keeping .dmg files on DVDs etc is no longer necessary. You can be sure any application etc. is out of date after a month or two.

I also do the same as iNAP and Kash. I keep a folder of all downloaded apps on an external drive separated into: not yet installed, installed and uninstalled.

I only keep the ones I know I will need (paid programs) incase I lose the disk, and some other programs which take forever to download.