Timing Belt Replacement on a Subaru

You can't. Regardless, they're easy to inspect: remove the upper left (driver) side front plastic cover's 10mm short bolt; pry the cover forward an inch and peek down at the t- belt...including its lower toothed return side; poke it with finger or pen to test the tensioner if you want. Surface cracks or a missing lower tooth indicates imminent replacement required. Usually they last a good 10 winters, independent of mileage. But always just check visually annually after 8 yrs age. Ern TSG/B

Online service has would have it noted, unless not done at a dealer. Otherwise, bolts/screws/hardware of the cover to the water pump housing will be clean of grease, and the seal should be new. Visually inspection if it has been recent would tell you.