I just changed my Mobil 1 after 5k. It looked great, I probably could have gone another 3k+. I say it depends on how good of a oil filter you have too. A lot of guys in here use Puralator, which I just took out. I heartily recommend it.

 

I also run Castrol (GTX in the rotary, and Syntec in the yoda) I notice a change in the synthetic oil color around 5 thousand miles, so it's probably due for a change.

I've read allot about this seafoam stuff, is it worth trying?

 

my 97 Taco I change the oil every 2-3K because i really don't drive it much. I've only put on 800 miles since last January, but i'll probably change it again here in a few weeks. Using a Toyota Filter

My 96 4Runner Every 3-5K Using a Toyota Filter

My Wife's 02 Accord every 3-5K Using a Honda Filter

My 84 Tercel Wagon (daily Driver) i just changed it today after 11K. I drive this car 100+ miles 5-6 days a week. 90% is freeway driving at a constant speed. This car also burns about 1 quart every 2000 miles or so. I check and add oil just about every other tank of gas (I get about 300 miles to a tank). Once i fix the leaky valve stems it shouldn't leak anymore. Usually i use the cheapest filter i can find for this one.

All of my cars run regular Dino oil in them. Someday i'll probably change to Synthetic, but i'm not in any hurry. I'm pretty impressed with the Tercel, it is a very robust car. I drive it pretty hard, and it has never let me down (except that one time the starter died... but a push start solved that little problem)

 

Obviously, you aren't in Alaska... my last oil/filter and air filter change was $79.95. And that was for plain ol' 5W30, nothing fancy. Considering I put about 3K miles a month on my Taco, that works out to $1,151 in oil changes per year if I did it at the 2500-3K mark... not to mention all those wasted weekends sitting in line to get the oil changes when I could be out enjoying life and spending that $$$ on gas and oil for the snowmachines!

 

Bout 3,000 min to about 7,000 max for me. Usually 4,000 though.

 

I just Pennzoil 10W-30 and Puralator filter every 2,500 miles.

 

Mobil 1 10-30 in my Taurus DD. 10K, filter every 5K. 90% highway driving