ROIs have converted from months to years with the edge too close, especially with exchange rates so volatile and testing new lows.
This isn't true roi is still in the months category. I'll use my 5850 machine for example. Its a rig with 5 5850's and cost me 1,375 to build. It can generate 1,900 megahash and requires 1kw.
That generates me 1.0750 btc a day which is 290 a month. At 8.5 cents per kwh (cost for me) it costs 61 per month. Which gives me a profit of 229.
Thats 6 months and lets be honest in 6 months the price could easily go up. If you save your coins and wait and at any point it reaches 20 dollars a coin you will have roi in 2.3 months. Keep in mind it only has to hit this once for you to drastically cut your roi.
So like I said roi's don't take years to recover.