There is no rule in our house on this. The only time I really ask DS to leave is when I'm getting dressed. We typically don't spend a lot of time in our room but sometimes we all like to watch tv together before breakfast or hang out while I'm folding laundry.
Our kids are still young, so we don't really have rules about our bedroom, but there's not a lot to do in there. We don't have a tv in the bedroom, the master bathroom doesn't have a tub, we don't keep any toys in there, and we don't let the boys sleep with
On weekends they do sometimes crawl into bed for a little bit, but they are usually more eager to get out of bed and do something more exciting. If DS1 needs something MOTN, he will call for us from his room. During the day, the boys run in and out of our room if we are in there, but otherwise ignore it. We are really only in our room to sleep, shower, and dress, so it's not a place they play much.
Her bedroom... Up until a couple of months ago, we lived in a 1-br. My daughter is an awful sleeper, and bedsharing was the only way that anyone got any sleep. I'm hoping to some day change this, but for now, I love the snuggles.