I just changed my oil today w/ Amsoil 5w30. It's been a bit over 2,500 miles since I last changed the oil, and I noticed that the oil wasn't very dark. I thought that turbo engines makes it necessary to change the oil every 3,000 miles, so my question is, is brown oil an indication that the oil could last maybe another oil change? Is it still protecting the motor just as well as if it was new oil? Who here keeps their engine oil in longer than 5,000 miles (what oil)?