I have been mining with about 3TH total for a month now. There have been 2 diff. increases,
one of about 20% and one of 3% ... however, my earning have not decreased by 23%..rather
my 2 week moving average only went down by about $5 daily...(more like <10%)
Pure coincidence (pool luck, BTC/$ rate) or what? Longer term (6 month horizon) what to expect?
There are a ton of things that can have an effect on earnings, and you've named some of them. First, let's take the BTC -> fiat conversion out of the equation. Given a hash rate of 3TH/s, you can easily calculate your expected daily earnings on any difficulty level. Every online calculator out there uses the same formula to determine this value.
Assuming you started mining on 6/24...
From 6/24 - 6/28 you were mining at a difficulty of 13,462,580,115, so you would have expected to earn 0.11207
BTC per day
From 6/29 - 7/11 you were mining at a difficulty of 16,818,461,371, so you would have expected to earn 0.08971
BTC per day
From 7/12 - 7/24 you are mining at a difficulty of 17,336,316,979, so your current expected earnings are 0.08703
BTC per day
Those numbers represent expected earnings based on your hash rate and difficulty. How your actual earnings compare to those expected values depends on the factors such as where you're mining. For example, if you're mining on p2pool and you're finding more than average shares, and the pool is finding more than average blocks, your actual earnings would be higher than expected.
