The hard part about pre-ordering next generation hardware is to predict a logical expectation of A) what will be the total network power (hashrate) be by the time your miner comes online which influences directly B) what will be the difficulty value at that time.
If you assume linear growth in the network vs exponential for example you will arrive at different conclusions. That is the real hard part.
At todays difficulty (now 908,350,862) a 2 THps miner at $1000/btc can expect to break-even in 5-6 days.
If looking backwards is any indication, the difficulty has increased by 945% in the past 90 days so if that is the same as the next 90 days and BTC values are fixed at $1000/btc you can expect to break even in 47 days.
IF you think that the next 90 days will grow faster (say 1.5x as fast) as the previous 90 days then you can expect a breakeven in 75 days.
What if your miner comes in 4 months from now instead of 3? What if a whole lot of people are buying one so that when they all come on line simultaneously the difficulty will spike beyond your projections?
And what if the price of BTC falls again from where it is now and stays lower?
A lot of what-ifs but you must know your variables before investing in mining capital.
possible duplicate of How much Bitcoin will I mine right now with hardware X?
– Murch – 2013-12-10T14:12:43.173@Murch Why downvote – user1704524 – 2013-12-10T14:46:12.013
I feel that the question is useful only to a limited circle of persons and for a short frame of time. With the changes we see in mining difficulty any answer will literally be outdated next month. This sort of questions don't help to build a time-lasting comprehensive question and answer corpus. It might be a better fit for bitcointalk or /r/bitcoin, where there is a stronger focus on current issues. – Murch – 2013-12-10T15:04:38.480
1
Underlying, is the issue that there are very many questions on our SE, that are essentially localized variants of questions that have been answered before. These create so much background noise that (to experts) more interesting questions don't stand out: I am motivated to take a harder stance on questions I don't find useful, since I read this Jeff Atwood: Optimizing for Pears not Sand
– Murch – 2013-12-10T15:13:13.557@Murch but the question relates to the upcoming release of mining equipment that will potentially increase the difficulty factor. And many people will invest in the technology would like an answer to these questions from the people that know prior to investing. If people don't mine how will coins be created? – user1704524 – 2013-12-10T15:23:35.057
1I am not suggesting that the topic isn't interesting, or your question is badly phrased. My point is that I feel that this question is a bad fit to Bitcoin.SE, because you are essentially asking people to predict the future in order to evaluate a product. Predicting the future is primarily opinion based (the SE format is not very good for discussion) and product recommendations are off-topic. Your question is well-phrased, but IMHO just not a good fit for Bitcoin.SE. – Murch – 2013-12-10T15:36:08.370
@Murch, I totally agree with you. There are to many questions regarding non-technical subjects, like investing money into the new generation ASIC-miners or the trustworthiness of some shady online wallet. I feel like we should do more to stop this and try to get the focus back on the more fascinating technology behind this cryptocurrency, but that's just my opinion... – Jori – 2013-12-11T12:11:17.827
@Jori Without investment in inoovation and technology it will be harder for this to succeed in the longer term. If we can provide advice that covers all aspects of this facinating and revolutionary technology we will all benefit. Things that will prevent mass adoption by the general non-technical public must be addressed by the community and that includes new investment into mining equipment, trading techniques and analysis or how to simply use bitcoin. If someone is unsure how to get involved at any level and cannot find answers to the simplest questions then we are creating a ringfence. – user1704524 – 2013-12-11T19:13:22.920
I sincerely doubt that there is a problem with the amount of investment in mining when I take a look at the difficulty/time chart. – Murch – 2013-12-11T23:23:44.053
Indeed Murch. Don't get me wrong, I too support the help of the non-technical public, but feel like that is not the task of this stackexchange. I don't know how the other active people here think about this, but perhaps its a good idea if we wrote some simple guidelines about subjects that are welcome here (i.e. in my opinion the technical site of bitcoin) and the subjects that are more suitable for a Internet discussion forum (like a quick starter guide for beginners), as this is a Q and A site. – Jori – 2013-12-12T09:27:30.900
@Jori: These things exists. Check out [about], [ask] and in general the [help]. – Murch – 2013-12-12T10:36:41.767
Oh, thanks! That's very helpful. According to the help topic about asking, investment advice is not allowed. Like I said, the original focus of this stackexchange seems to be more technical.
– Jori – 2013-12-12T14:26:12.663