After long study, I have inferred that the STBs are capable of running trouble free for one year only (3 Hrs Viewing/Day) This one year may be slightly increased by providing ventilation at the bottom of the STB. But if you observe DTH operators's offer pattern, near Diwali time they give STB with one year top-up at much discounted price. Eg ADTV give SD STB with one year freee viewing at 1800 Rs (Rs 3000 in case of HD). If you calculate this would be almost one year subscription price . ie STB is totally free.
I suggest our members to buy new connection every year during the offer period. Then you will be a trouble free viewer. More over by changing new connection every year, New updated Channels are added with out ant addl cost.