I'm amazed at how many people only have one key for their car.
Always get a spare made and leave it with a friend who can get it to you.
Yes, I always get a spare door-only key cut, for the little it costs its pointless not too - especially with cars that are capable of locking themselves as some do!
Care with the "friend" selection Gibbo
I gave a spare key to my van to the Mrs and when my main key malfunctioned (was bent) I asked her for the spare.
"In the glove box" she says
You'd be amazed at how many of those magnetic key-holders you find carefully hidden away under the dash!!!