With double doors you will need space to open them, much more than you will need with a single door (er, twice as much!).
When I was growing up we had sliding doors (sometimes called "pocket doors") between the living room and dining room. When they were open they slid right into a gap between the two walls, so you could completely open the two rooms up to each other, which was great for occasions where you had a lot of people and need to be able to use the two rooms. And they needed no space at all for opening in either of the two rooms.