https://bitcoinwisdom.com/bitcoin/difficulty-> 9 month chart
Difficulty from 2016 July to Dec. Went up from Close to 200 to just below 300. Nowfrom December it has went up from just below 300 (let's say 290) to 422 and after 8 days it will 450 or so. 2 new Batches of S9 which will start minning in March. And diff will alredy be in high 500's maybe even 600. If BTC price don't follow diff, you be in losses in autumn and contract will be terminated.
Difficulty from 2016 July to Dec. Went up from Close to 200 to just below 300. Nowfrom December it has went up from just below 300 (let's say 290) to 422 and after 8 days it will 450 or so. 2 new Batches of S9 which will start minning in March. And diff will alredy be in high 500's maybe even 600. If BTC price don't follow diff, you be in losses in autumn and contract will be terminated.
Maintenance fee when i start (07/2016) was 0.008/10GH now is 0.004/10GH What will be a few months? Maybe you already know?
Update 15.02.2017 Maintenance fee: 0.0035 $ / 10 GH/s / 24h