Creating something as powerfully destructive as the Death Star takes one thing above all: an insane amount of money. As if building the iconic weapons wasn't a cash draining enterprise in and of itself, keeping the lights on is a feat that surpasses nailing an exhaust port with a torpedo, while using the Force. Destroying a Death Star is easy, but paying $7.74 octillion to make it work day by day is extremely hard.
Ovo Energy crunched the numbers, and came to the conclusion that the $7.74 octillion cost for operating the Death Star would be around what's required to feed, quarter and launder all stormtroopers on board. On top of that, the cost factors in the usage/recharging of the Death Star's powerful planet destroying laser canon, as well as jumping into hyperspace - because having that much firepower and that many grunts aboard a craft that can't move or shoot is about as useless as building Noah's Ark without any sign of a flood.
While it may seem like a silly Star Wars tidbit, all of the monetary studies examining the Galactic Empire's weapons programs and economic stressors do help to explain just why people were so damned unhappy in the Empire to begin with. When you have two power hungry Sith as your top statesmen, they're obviously going to blow all of the money they have with only that goal in sight. All other causes fall by the wayside. Only those who join and obey are rewarded, and conscription ultimately enslaves the youth of the Galactic Empire just so the wheels can keep turning, and star systems can fall under the power of Darth Vader and Emperor Palpatine.
Those aren't really things people tend to keep in mind when viewing the story of the Skywalker clan and their associates, but they make their plight all the easier to relate to. Of course, one also has to ask whether the Empire would have been able to sustain itself even with a Death Star or two actually still in operation. Eventually, one would expect the economic stress to collapse the whole damned thing, which may or may not have been a better way for the Rebels to go about their business. Warfare is effective and all, but economic sabotage just might have done a better job, with fewer lives lost.
Of course, warfare makes for exciting movies, and Rogue One: A Star Wars Story will benefit from that fact when it opens on December 16th.