Spare... Additional... Extra... Second best

Spare key... Spare wheel... Spare friend... Spare girlfriend... Spare fun...
Anything spare... Just the idea of being the extra or additional thing used if the original thing of its same kind fails to function...
It is usefull, and serves a great purpose... It is usually used in emergencies and is of great value and importance in these moments...

It is never the main wheel.. nor the main key... It is usually kept aside till the time to use it comes.. Always left or kept in some place to be used when needed, so it is a "when needed" thing...

It can never be the first, the main, the important, the initial... It has to always be placed as second, except of the first is lost... And even when the first is lost, the spare will always be treated as the second best that was resorted to because the first or the main was gone... was lost...

I am the spare key, the spare wheel, the spare friend... the spare that will always be the second best... but never the first choice... never the "First"