[citation][nom]computernerdforlife[/nom]I use fully synthetic engine oil and I check my engine oil bi-weekly to make sure it says full. (I'm not talking about gas that you get at a gas station). The cost for the oil that is compatible with my engine is Mobil 1 Full Synthetic at about ~$100 which is double the price of non-synthetics out there but the quality is much more reliable between oil changes. My point is that if it's better than what i'm using now, i'll take the temporary alternative that actually makes my car run on a daily basis. Good news is good news, even in small doses.[/citation]
The reason why synthetic oil is ~double the price of standard oil is because it generally takes more time before it breaks down. Synthetic oil provides zero performance or functional advantage over standard oil--regardless of what the marketing says. If you change your oil ever 3k miles with standard oil, or every ~5k miles with synthetic, there will be zero functional impact on your engine over the lifespan of the car.
From a conservation standpoint, synthetic makes sense (one would use a lower volume of synthetic oil over the lifespan of a car than standard oil, so we're not consuming as much or generating as much waste), but it has no functional benefits over standard oil, except you don't have to change the oil as frequently.