Subaru 1999 Legacy Owner's Manual page 366

D Do not let air out of warm tires to adjust pressure. Doing so
will result in low tire pressure.
The tires should be checked frequently for proper tire pressure, wear,
and cuts.
B Checking the tire pressure
For the best balance between fuel economy, tire life, ride comfort, and
handling, tire pressure should be maintained in accordance with
specifications. Check the tire pressure when the tires are cold. Cold
means that the vehicle has been parked for three hours or has been
driven less than 1 mile (1.6 km).
The recommended tire pressure and sizes are provided on the tire
inflation pressure label, which is located under the door latch on the
driver's side.
Tire wear will vary with each wheel. To increase the life of tires and keep
wear uniform, it is best to rotate them every 7,500 miles (12,500 km).
When rotating tires, replace any unevenly worn or damaged tire. After
rotating the tires, adjust tire pressure and be sure to check wheel nut
tightness.
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