Our 2011 Honda Civic DX is about to hit 200k soon so warranty has been long gone. This Civic is daily driven with mixed city & freeway driving with sevaral stop/starts thruout the day as my wife drives house to house to see patients. I've been using mixed brands of synthetic 5w20 from what's usually on sale at Walmart or Costco on time per oil service indicator. Our weather gets cold in NorCal, but not freezing (unless we're in Tahoe/Reno sometimes). Summers can be 100-110*F. Should I switch to high mileage? 5w30, 0w maybe?? Longevity of the motor is more important to me vs. gas mileage.