When we dug into this house, we decided we would keep all the original doors and door knobs. Last week I found myself stuck in my bathroom when the old door knob malfunctioned and I ended up spending an hour an a half waiting to be rescued by my husband!
I didn't have a cell phone with me but luckily the room does have a window and I was so glad when my neighbor came home and was able to yell to her from (2 stories up). "Can you call my husband? I'm stuck in my bathroom!" (It's a very funny story and someday I'll share it in more detail).
Needless to say, we replaced the door knob with a new, functioning one! It's perfect.