I just switched from Chevron Supreme dino to Schaeffers 7000 Supreme 5W-30 in both my Honda 2000 Accord and my Honda 2002 CRV-EX this weekend. The Accord has 38K and the CRV has 21K miles. Would I be better off doing an oil analysis when I change the oil next time or should I wait until the 2nd change using the Schaeffers? Or should it even matter? My wife puts more miles on the CRV and it will be next for a change. I was considering going 5,000 miles and taking a sample for analysis, changing the filter, and topping off until the analysis results come back...hoping to go another 3-5K after that if analysis warrants additional interval. Would if be beneficial (or just wasteful) to do a complete change at 5K and then proceed with this plan the next time around?