Equipment Repurchase Calculation Help

[Vaesse]

My husband has done all of the real BitCoin research, and while I have kept up fairly well, there is a question that I'm trying to figure out that he has no answer for nor willingness to try to come up with an answer.  And it's quite possible that either he or I are misunderstanding something basic making my question irrelevant or complete nonsense.

He says that if I get a (for example, not attempting reasonable numbers) 1Gh/Sec device that earns $10 in a given time period, because of the change in equation difficulty, it will eventually earn only $5 over the same period.  I have no name for this phenomenon, but for the sake of this message, I'll call it splitting.

What I'm trying to figure out is a VERY rough approximation of how often this splitting occurs.  I understand that it depends on lots of different factors.  I understand that changes in the number of miners, the equipment, etc. will change the time between splits.  I understand that it's likely that it's not an even frequency, likely it's getting more frequent as time progresses.  But is it multiple times every day or every five years or once a year or once a month?

Obviously, if I'm planning to count on the income earned from the miners to any degree, I'll need to double my equipment about that frequently.  I'm trying to figure out how much (percentage) I'd need to reinvest in equipment to keep my earnings approximately the same.

I tried to look at some graphs, but since I don't even know what I'm looking for, I couldn't begin to calculate it.  Any assistance in this regard would be greatly appreciated.

[Zephir]

The basic idea of btc mining is, that every 10 minutes a block should be solved, after 2016 solved blocks, the difficulty has to be adjusted, because the more processing power someone put into the network, the faster the blocks get solved. Normally it should take 14 days to the next adjustment, but due to the processing power increasing it took everytime only 10-13days in the last year.

To get more knowledge about the terms: difficulty, blocks, etc please read the inofficial bitcoin wiki: https://en.bitcoin.it/wiki/Mining

To calculate your earnings, you have to use a difficulty calculator: http://www.evolyn.net/bitcoin/mining_calc.php
                                                                                     or: http://btcinvest.net/de/bitcoin-mining-profit-calculator.php

You have to know, the times were you made big money out of mining are gone, too many fishes in the sea, it´s profitable for the sellers of ASIC Hardware and for those with near zero electrical costs, or big mining facilities, but not for the "small homeminer" anymore.

Like I always said: Just buy coins instead.

[PenAndPaper]

Just to clarify that the amount of bitcoins a miner produces for a given period doesn't get halfed every time the difficulty readjusts.

For example today and for the next 2 weeks lets say that my miner can produce 1 bitcoin/week.
After those two weeks the "difficulty" will change and most probably will increase because more miners will enter the mining business.
My miner will then make something like 0.8BTC /week. After 2 more weeks when the difficulty readjusts again my miner will then make lets say 0.55 BTC /week and so eventually it will become obsolete...

[Domino]

Just some additional info, you can find the historical difficulty change on https://bitcoinwisdom.com/bitcoin/difficulty

For example, bitcoin difficulty went up 20% on Aug 19, and so your mining revenue should be just 1/1.2 = 83.3% than before.