There is no miner with less than 1W/GHS. With makes in 5 years 50.000 kWh witch is min 5$ power expenses. You are now saying that you for the remaining 3,75$ you want to change hardware several times? Beside costs of Hosting maintenance etc...
I beg to differ that there is nothing less than 1W / Ghs. I suggest you do a little research.
And even if you were right (which you're not), over 5 years there will be plenty of times to get more efficient power consumption as ASIC technology advances. It only takes 1 change to completely destroy your estimate of $4 over 5 years. Just ask the miners who are going to be changing out their avalons for neptunes, etc. Nobody will be mining with the same hardware 5 years from now.. that's just silly. That would be like someone still CPU mining for Bitcoins.Anyways, I'm going to go and compile my payout list (its payday today!
) so have a great day. 