I need to know few things
How much power (watt) do you need to run one unit ? Standard psu can handle how many units ?
new blades takes 100w and need 10A. If, for example Corsair 650w PSU has 52A on DC rail, you can safely run 4 blades with it.
What internet connection is preferred to run entire month ?
once during emergency I run 22 blades and 2 BFL Singles for one week or little more on Galaxy note 1 3G wifi tether. Bridget WIFI to LAN and all was running just fine.
As criteria of good internet, you can use ping time from your computer to pool server. Airtel and most private ISP will give better ping for sure, compared to BSNL. But that does no matter really, traffic is small anything will work just fine.
Warranty - If there are defects / unit failures will you replace the units ?
yes it come with 6 months replacement warranty. It does not cover such things as connecting DC wires without keeping polarity in mind.
Whats the longevity of the unit if you run nonstop for months
Blades made up to industrial standards, it is real hardcore instruments. Longevity may be more related to the way you running it, rather to blades it self. High quality power supply is a must, high quality power back up too. In short less on/off cycles longer you blade will mine.