Im wondering if I should replace the spare tyre on the car, its been used for maybe 15 miles tops and is in perfect condition, however its now 15 years old, its the original Continental one.

 

Has anyone else swapped theirs out of interest?

Are there any micro cracks in the rubber? Does it still hold pressure? Tyres degrade mainly due to the action of sunlight on the rubber - if the tyre is stored in the boot it is immune to this effect.

It looks perfect, pressure is fine too.  That was my thinking.