I'm planning to buy parts to make this rig:https://en.bitcoin.it/wiki/Mining_rig#One_ATI_5830,_Approximately_245_Mhash/s
In about a month.
In a month will I still be able to get the same overall profit as I could with that now?
I realize the difficulty is increasing which means you make less bitcoins, and therefore less money, but doesn't that also mean a relative increase in the value of each bitcoin which should even it out?
As the value of bitcoin increases, one would expect the amount of cumulative mining processing power to increase as well (obviously, the more it's worth, the more people see money in mining it).
As the mining power increases, the difficulty increases, which in turn decreases the return a given amount of processing power would create.
So, here's how I look at it: The more people who mine, the more people who split a relatively fixed number of bitcoins being generated. HOPEFULLY that is all being driven by the increase in value of bitcoins, so your actual output would hopefully stay consistent.
But here's the trick...what if the value of bitcoins plummet? Will that cause people to stop mining? Maybe. Maybe not? They have a bunch of money invested, so would they see that they're spending too much in power and get out? Or would they continue to mine in hopes that the value returns?
Short answer is, there is absolutely no way of knowing. I advise everybody who asks me to NOT buy a dedicated mining rig, but to instead just beef up their primary computer....that way, if you decide to stop mining, you're not really out anything.