Mining conditions
Due to the demands placed on the equipment, it's crucial that it be kept and maintained in a proper environment to sustain conditions for peak performance.
Most notable are the cooling requirements. Air conditioning may be required to maintain a constant temperature for the equipment to operate. Make sure that you factor a cooling system into your budget and design.
Electricity usage from both the equipment and the cooling must be assessed and arranged. Clean and stable electricity is important so as to not damage the equipment. Electrical spikes and high loads can cause interruptions to your mining operation.
Constant monitoring of the equipment is important. Downtime could result in a much lower return on investment than anticipated. Thus, it is common for serious mining operations to have a full time staff to monitor the conditions and maintain the equipment.
Mining pools
It can be quite difficult for a single ASIC miner to find the necessary proof-of-work to earn the rewards...