Is there a way to retrieve your work after a crash, if you haven't saved for a while?
I found this pretty useful technique using the "actions" panel to autosave. http://vector.tutsplus.com/tutorials/scripting/autosave-in-adobe-illustrator-using-the-actions-palette/
In case that link ever goes down, the basic idea is to create an action set 'Autosave' containing two actions, which each trigger each other, creating an infinite loop.
Then, in one action, add a 'Save as' saving to a file you can use as a recovery file, placed somewhere logical, as well as a pause in each one for half the amount of time you want to leave between saves.
If you want a longer pause than the maximum 100 seconds, put a pause in both actions, saving every 200 seconds - just over 3 minutes. If you want longer (e.g. every 5 minutes), add an extra action to the loop with another pause.
As of CS6, no there is not an auto save feature in Adobe Illustrator.
If you're on mac, you can make an applescript that does this but it's kind of a pain in the butt. Here's a link to a similar one written for photoshop. You can probably tinker with it a bit if your up to the challenge to save yourself some headaches.
Of note. AstuteGraphics.com has released the AutoSavior plug-in which is designed to auto save at user-specifed increments for Illustrator CS5+. It is a free plug in.
One small tweak to the Actions method: instead of Save As use Save a Copy. This way you are creating a backup copy in a location specific for backup copies and you can still save your original in the place you want it.
If you're on a Mac then you can also use the "Ai Auto Save" app available on the Mac App Store here.
Note: for the sake of transparency, I'm the developer! I made the app after experiencing the frustrations discussed above. Hope you find it useful.
There's an app for that. Works brilliantly http://www.tool-forcesw.com/foreversave/