Well, I am no expert...and people should correct me if needed...but I would say that it will depend a lot on your room temperature. If its pretty cold in your room (lets say, less than 70 for example), then I would not leave your beardie out too long. If its warmer then you can leave them out longer. Just common sense I guess.
My beardie, Bandit, will hang out with me and run around my room for awhile; and when he is done, he will just run to his tank and 'claw' at it (so I let him in). That usually at most lasts about 15 to 20 min (if its pretty warm in my room). Some days I will let him sit on the window sill where he stays warm (usually about 90 there cause the bottom is black...I put him on his blanket though for comfort and not to burn his belly). He will sit in the window watching people for over an hour (he cant fall because my bed is right next to it; same level). When he is done with that, he runs onto my bed and runs to his tank (I give him a ramp from my bed).
So, overall....I would start off with taking yours out for small amount of time. Just get to know your new beardie. I took my Bandit out about 3 times a day after he got used to his tank. He is 8 months old now and he loves me now...haha. If im gone for a long time, he will run back and forth in his tank till I pick him up. Or, if he sees a bird outside (or whatever makes him nervous) he will actually run to me and sit by my foot. Not making this up to be cute either...I actually find it interesting.
FYI, I like to rant.....getting back to YOU, keep yours out for sort amount of time at first and gage for yourself and how your beardie feels (they should always feel a little warm to the touch, start off with that). Again, other people PLEASE correct me if im wrong..but thats my 2 cents. Good luck! Post pics!