My D has used the same password on her accounts since early teens (when it was our requirement that we have access). Not only does she know I still have access to her FB, but she'll send me emails saying, "Something just happened, but I don't feel like writing it all over again. Check my facebook."
And my boys know that, since I have access to her page, and they are "friends" with her, I can see theirs, too. They seldom post anything exciting, though.
But my oldest does put photos there now and then - easiest way of sharing them with me.