You must keep the dust out of your miners make sure they stay clear of dust , make sure you watch the temperatures too if you see ne getting hotter than usual you should check out why, make sure all the wires are normal temps as well. feel your wires frequently that plug your miner into the wall, if that wire gets to Hot check the Guage of the wire and get one that does not heat up. Fire prevention is the best policy.
If anyone has any mining equipment that they no longer want/need because it uses too much electricity with the current difficulty to make much profit.....if you don't want them I will GLADY take them off your hands. Let's just say I have free electricity. I split the mined profits with you even if it's something worth doing 500GH+ or something.
I remember when my 5GH/s miner would easily make $175 in a month. Now a year later I'm lucky to make 52 cents in a month...wtf is up with that.
Both the raise in difficulty and the price drop in bitcoins will effect your income.
I can sell you some miners if your interested shared profit s not something I am interested in.