synthetic is usually better.. I have went with ext interval now too.. like Mice.. I go bout the same.. but I might go longer as there has been a guy that has a fleet of vehicles that he'* been using the same oil as me.. Esso XD-3 ( Canadian Exclusive only.. woo hoo.. one thing that we have that you guys in the south don't for once. ) and he'* went 20K KM, did a UOA.. and said it was still fine.. shear and wear value isn't much off virgin oil, so he'* going to try for 40K Km.. thats a lil much for me.. 15K KM max is wat I would go.. and with my schedule for the rest of the month.. I won't be able to make it to the Esso distributor to pick up the new batch of oil till probably 15K.. in which case, I will send a sample in for UOA and see how well it held up..

I will agree also that the oil filter is probably one of the most important and forgotten part of the oil system.. No Fram for me.. Purolator, Wix only

I think the benefits are easy to define, but they're more relevant to some people than others. I'm thinking mainly of the more consistent viscosity at temperature extremes, which would be really useful if you're living someplace like northern Wisconsin and you need the car to start when it'* -27°F outside, or you're doing endless highway miles through Death Valley in the summer.

But if you're just putzing around town and occasionally on the highway in average weather temperatures, I don't know how much benefit you're really going to get in exchange for the higher price of synthetic, plus that kind of driving fits the Severe Service schedule where you're supposed to change the oil more often. My cars run on regular dinosaur juice, with changes around 1500-3000 miles each, and they're doing fine: no sludge buildup, everything looks clean inside the rocker covers, and the old oil is dark brown but not opaque black when it comes out.