Subaru FB-series engines have a known oil consumption pattern that makes oil change intervals more important, not less. We do every Subaru oil change with 0W-20 full synthetic (or 5W-30 for older EJ engines), an OEM Subaru filter, and a new crush washer.
We check for leaks at the timing cover, head gaskets, and cam carrier seals at every visit. Catching a Subaru oil leak early is the difference between a $200 reseal and a $4,000 engine.