Hm, I thought the increase in difficulty was fairly predictable. I'm looking at the CoinTerra miner at
https://cointerra.com/product/terraminer-iv-1-6-ths-bitcoin-miner/ which uses 4U space which is perfect for my rack.
Anyone here can share some information about how many bitcoins you're able to mine in a month and what hashing power you have?
I'm thinking about choosing between two options with which I ultimately want a small reserve of cash and bitcoins to be able to start an automated exchange service.
1) Spend 10% of my income every month and buy some bitcoins and keep it
2) Spend a large amount now and mine little over time.
Fairly predictable as long as a new strong player or new strong technology arises. In lifetime of a miner (which will usually be 8-12 months where it will be able to cover its on going expenses), it is possible that this could happen which could make your calculations go wrong.
Practically 0.0375 btc per TH/s per day is what you can earn right now.