The key to my front door, esp the one hidden in my hallway when my cat runs out and I run out after him into the hallway and the wind blows the door shut...
I have been locked out that way many a time b4 I hid the little key in the hallway - I won't say where. far from my door, needless to say. Sassy
No one ever talks about this sort of thing. We hide a set of keys and have given other sets to our neighbors and it has saved us sooo many times. And the best part is when immediately after you realize you have locked yourself out and are about to curse yourself for being so stupid, you remember your hidden key and feel like a champ again. (Thanks, Sassy!) MGR
(Re-edited from a post published 04.18.05)