After using your jack for some reason, ever spend an extra 10 minutes trying to get it back into the trunk space? First you screw it up... then down, then back up. An easy way to get the jack lined up is to paint a red dot on the jack's main lifting arm and the main body. When the two dots line up, you just fit it in and screw the wingnut back down.
Also, when removing tires, it is advisable to paint a dot on one of the bolts, and on the bolt hole on the wheel. This will help you line up the wheel when refitting back on, and assure you that the tire balance will remain the same. This is important if you have your tires dynamically balanced.