With all this talk about whether we're going right over the cliff, The Takeaway started thinking about the patterns of budget cycles.   These sorts of down-to-the wire negotiations are actually rooted in the political back and fourth of budget cycles that started years ago. The notion of the ten year budget and fiscal cycle is actually a rather common one -- but why? It takes ten years, apparently, to shoot for big overhauls in the budget. Tax structures get a hard look and potential revision every ten years, even those pesky Bush tax cuts that are up for renewal have a ten year expiration date.But why ten?   And is it possible to determine, based on our current tax structure, where will we be in ten years from now?Charlie Herman, economics editor for The Takeaway and its co-producer WNYC says, it's a pretty arbitrary time frame.