Good idea to check the air pressure in your spare!
This morning I was detecting a slight drift to the right, and when I got to my destination, it was obvious that my my front-right lo-profile tire was low on pressure. Not wanting to jeopardise the tire any further by driving on it (to a gas station with air), I chose to install the space-saver spare that's been in its original trunk location for over 10 years. Guess what?? Pressure in the spare was down to under 10 psi!
Good idea not to assume that just by sitting unused in the trunk that the spare will be up on pressure when you need it.

 

Or you could just keep a cheapo tire inflator in your trunk.

 

and don't forget the tire repair kit. $20 in total at your local wal-mart.