They are not just the concept of a room, but the membership of a college, which needs to be paid. After paying, you can participate in all activities, including dinner, entertainment facilities, music room and so on.
The fees are generally expensive, and some colleges even cost between 50 and 90 pounds. There are also 15-25 pounds, but I think many undergraduates take the initiative to pay. They think the JCR meeting is very important and necessary.
Most colleges are free to use these facilities after paying an annual fee. Of course, you don't have to pay this fee, but you may not receive these regular activity emails from the common room.
After you enter the college, there is a welcome package, which will tell you all the expenses, some of which are necessary and some are voluntary. For example, Aidan's gym weighs 25 kg, which can be used for one year and is completely voluntary.
JCR and SCR are both very powerful and have their own special websites, which are different from official website University. This is an example of St Aidan Church. I can click on a website like mine to automatically register for payment, or go to book's own formal dinner and other activities.
Of course, some colleges are divided into JCR and MCR, which are all the same. If a college has MCR and SCR, it means that they count the faculty into SCR, and MCR only includes graduate students.
If you don't know the common room, recall Harry Potter.
Harry, every time after class, they will knock on the portrait of a fat woman (of course, the password of Durham's portrait becomes the password on the door of the accommodation area, and only by pressing the right password can they enter the closed area of the college area), and then they will enter the Gryffindor common room.
There are all kinds of entertainment facilities and fireplaces in the lounge, which will be found in every public lounge in Durham. You will meet many people from your own college here. In other words, the common room is the most important part of college social life.
The common rooms of colleges are basically closed to the public, except for activities such as inter-college friendship (of course, the common rooms are different from bars of colleges, and bars of colleges can enter at will).
You can also play Wii in Saint Aidan's common room, which also has guest rooms. You can also rent a DVD from Potter to watch it.