Revisit your calculations. You might be thinking "It's no problem, at the worst, I break even and get the hardware for free within X days." You need to run your calculations for the next 3 months assuming MINIMUM +90% difficulty per increase, and a $10 BTC price.
I'm the first to convince people to project conservatively, but this is silly.
Do I recommend projecting your rig at $10/BTC? Absolutely. It needs to be profitable at that number.
Do I recommend projecting 90% difficulty increases? Absolutely (at least in the short term). It needs to be profitable at that number.
BUT, there is no way you'd see both $10 AND 90% increases. At the current price I would think we'll see 50-70% difficulty increases in the short term. At $10/BTC I think you're looking at more like 20% in the short-term and 5% in the long-term.