Quote from: bitcoiner49er on August 29, 2013, 03:14:32 PM

Quote from: kano on August 29, 2013, 02:52:58 PM

For a 0.335 GH/s device to recover 0.17BTC with only a 20% diff each change ... it would take ... 190 Days
... at 1000 days it is ... 0.17936377 BTC (so pretty much never reach 0.18 BTC)

If on the other hand it was 30% diff each change ... at 500 days it will have generated ... 0.11957525 BTC ... 1000 days ... 0.11957587 BTC ... so it would never reach 0.12BTC ... of course 0.5W isn't free either ... especially after 1000 days ...
http://www.tradebtc.net/bitcalc.php

For a 10GH/s device at 20% increase each change, it would take 89 days to get 4BTC
at 30% increase it would ... 500 days 3.56940335 BTC ... 1000 days 3.56942180 BTC ... so never reach 3.6 BTC
But the electricity is pretty relevant also ...

Yes many people buying AsicMiner hardware will not get their many back ...

The big question and decision point is: Where does 20 or 30% stop each difficulty increase? I don't see 30% happening for 500 days. Although I COULD be wrong here.

At 30% 500 days is irrelevant since ROI maxes at around the 165 day mark (approx 3.554BTC for 10GH/s)...another 30 days more if your electricity is free. Then its a doorstop.
We are talking about the current offerings. What hardware and what prices will be in 500 days is anybody's guess.