My wife has a 2012 Toyota Venza with a V6 I think it's a 3.5 anyway when she bought it they insisted she change the oil every 10,000 miles and since they were doing the oil changes run only Toyota synthetic oil. Now at 35,000 miles the dealership has changed there minds and recommend oil change every 5,000 miles and we can use either Toyota oil they offer either Dino or Synthetic. So what should we do? Any advice?