Bedroom door open or closed?

My 8 and 9 year old boys just their own room. They used to share room but they were fighting aver everything. I know that each family is different but should I let them close the door when they go to sleep or look it at any time?

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    About Susana
    Born: Rock Hill, South Carolina
    Current: Rock Hill, South Carolina
    Birth: September 02
    On since: Jun 30, 2014