Thank you for helping, I'm grateful to be chatting with people actually doing mining
Have you found that you were able to remain profitable regardless of mining difficulty increases?
How long have you found your rigs remain profitable before they are surpassed by superior technology? 6mths? 12mths? More? Less?
Have you factored in labour time requirements for this or has this not been physically included in the expenses section of COGS?
Time between miner models is strictly set by what the semiconductor industry can provide. So far even more than 2 years after 16nm video cards and CPU's started shipping at all they are *still* tweaking the 14/16nm nodes. Bitmain released the s9 (16nm) in early 2016. My crystal ball says miners will remain at 14/16nm for at least another year, probably more.
Labor? 25-30 miners does not take up much space, time involved is mostly unboxing and a few min to plug in/setup each one.
since you are rightly taking a Business approach, check what your countries tax code says regarding business equipment write-offs.... in the US especially, check out Section179.org. A licensed small business can write off up to $500k this year
The IRS has already issued Guidance on miners and treat mining hardware the same as any other computer device needed for your business.Also, here mining income is treated the same as the Metals market - taxes are only applied to coins (or metals holdings or real metal actually mined from the ground) when they are converted to fiat, in this case US$. So, you can hold and accumulate coins as long as you want with (so far) zero tax liability and the Taxman only wants his cut when you cash out.