The 6-cyl CVT's (Murano, Maxima, and especially the Pathy which is a monster) are definitely hardier than the 4-cyls. My feeling is it's a factor of applied area on the belt. Absent any overheating, the 4-cyl's seem to beat up the fluid much quicker than the 6-cyl's. Since erosion of film strength from shear forces is the primary factor that degrades the fluid, the smaller belt surface area of the 4-cyl's seems to have a huge effect. That doesn't necessarily mean you can or should stretch out your intervals on a 6-cyl, that's a decision you need to make based on your own driving and circumstances. The two big shear-producers for most people are having a lead foot or routinely driving in steep/hilly areas. If you live in Flatsville Flats and drive like grandma, you can probably get away with a lot -- but the fact is, that isn't bloody likely for anybody who owns a ScanGauge and posts in this forum. My advice for any CVT owner who's in it for the long haul is 30K maximum and do add a cooler, with a bypass valve if you live anyplace with 4 detectable seasons.