I have been putting Mobil I or Syntec 5W-30 winter and 10W-30 summer in our Subaru and at 94K miles it runs great and does not burn any oil.

I change it twice a year. We put about 10K miles on each crankcase of oil.

I have also discovered that super premium gasoline gives superior mileage but not better economy. I suspect the higher octane means the knock sensors allow maximum advance.

99% of the time we run regular but there is a difference with Sunoco 94 altho hardly worth the expense.