I grew up in a very "open" home and this is the way DH and I decided to be too. My kids have friends stay overnight a few nights every month, and we have friends and family who live far away or abroad, who visit us a few times each year. Everyone around us knows they don´t have to call first to come and visit, and we always have food for anyone who would like to join 

But otherwise, not really.
Since they've moved, they've had.. my 13 year old cousin, my uncle, my grandma, two of their friends, and DFi and I stay at their place - each for at least a week at a time. 