edit: My bad, it was the iPhone 4 prototype debacle! But he directly answers the question about how far he works ahead. http://www.dilbert.com/blog/entry/thatlost4gphone/
But if this is just an online version (it is /fast, whatever that means), it might be a different story.
If he even has the ability to get one approved and published quickly, which I'd say is doubtful given that it's print, it's probably a nuclear option that he wouldn't use for having seen a few threads here.
"We look for places where the math is right. Meaning what? Meaning that pop. is about to explode---we can predict that just by looking at age histogram---and per capita income is about to take off the way it did in Nippon, Taiwan, Singapore. Multiply those two things together and you get the kind of exponential growth that should get us all into fuck-you money before we turn forty.
This is an allusion to a Randy/Avi conversation of two years ago wherein Avi actually calculated a specific numerical value for "fuck-you money." It was not a fixed constant, however, but rather a cell in a spreadsheet linked to any number of continually fluctuating economic indicators. Sometimes when Avi is working at his computer he will leave the spreadsheet running in a tiny window in the corner so that he can see the current value of "fuck-you money" at a glance." - http://www.cryptonomicon.com/text.html
[1] http://news.ycombinator.com/item?id=1513390 ; Replies to the parent comment include other 1980s references to the term.
My first recollection of it was one of Casey Kasem's tirades back in the 80's. I can't find the original on the web, but Bob and Tom spoofed it with "Mr Obvious - Too Hot for Radio" - http://www.youtube.com/watch?v=1Vobd2qDpzU
I recommend this book, by the way. It's strangely inspiring. Get the audiobook for the full effect.
Nicholas Taleb has a similar explanation in one of his books (probably Black Swan).
Like many here, reading Dilbert is a special daily event for me. In my case, I wait until my first cup of coffee is brewed. It must be awesome for Scott Adams to be able to give so much pleasure to so many people, and make a good living from it.