De-authorize individually.

You can. You just have to physically have access to the device to do it.

http://support.apple.com/kb/HT1420

If you have direct feedback for Apple about Authorization, send feedback here:

http://www.apple.com/feedback/itunesapp.html

This forum is filled with users like yourself. We have no insider info or access to software changes/development.

After you reach five authorized computers you can deauthorize all and start over.

Will deauthorizing and starting over loose access to any apps and/or information?

No. You will not lose any content. You will simply have to (re)authorize any machines containing the apps in order to use them on that computer.

this is all worng/ outdated: you DON'T HAVE TO DEAUTHORIZE THEM ALL. JUST GO TO YOUR ACCOUNT AND THERE YOU'LL HAVE THE CHOICE OF DEAUTHORIZING ONLY THE DEVICE(S) YOU WANT TO.

No, this is not outdated. Authorization of computers and management of devices are two different things. See support docs with more info here:

Managing Devices: http://support.apple.com/kb/HT4627?viewlocale=en_US&locale=en_US

Authorization: http://support.apple.com/kb/HT1420

If I "Deauthorize All" computers, does that include iOS devices as well? Do they count as "computers"? Or is computer defined only as a desktop or laptop?

Authorization applies to computers, not devices.