You're situation is different. Many have small rigs (<10 GPUs) who live in old apartment building (where power is a flat rate) or get free electricity from Business/University.
Right now an R9 270X is worth about $100, in one year, it will most likely be worth $80-90 or so. They already depreciated to the max.
At the moment an R9 270X only makes $0.25 per day. After 6 months thats $45. From there the daily profit might either stay the same or become lower.
So the point is, if you have free electricity just keep mining. You already missed the boat to dump the GPU before the price fell.