Hello everyone. Like many others, I found this site a few months back and feel like I finally have a place to go to get my fix! It's really nice to know that there are others out there like me (mad scientist laugh in the background...) Anyway, my question is as follows: I've been doing a lot of research on motor oils and filters, and one thing that I am seriously wondering about now is whether or not it is better to use the same brand oil all the time, or if it is better to switch brands at every oil change. The reason I ask is that out of all the topics, discussions, forums, and research, it seems that there really isn't a "bad oil" to use anymore, but that each brand seems to have different strengths and/or weaknesses. For my example/question, let's assume the viscosity stays the same (5w-30,10w-30,...), and that either a synthetic is always used, or a dino is always used. Also, oil changes are done every 3,000 miles. HYPOTHETICALLY, let's say Brand X has great anti-wear, but not great anti-foam. Brand Y has great anti-foaming, but not so great of a pour point. Brand Z has a great pour point, but not a great detergency package, etc. Getting the idea? Now let's assume that Brank K is used solely, but it has a low TBN. To me, it seems that by constantly switching brands between Brand X,Y and Z, you'd be getting the best overall packages over the live of the engine, whereas by using only Brand K, its' weakness will not be masked. It's just that I've heard time and time again stories of people who use "whatever oil is on sale" taking apart their engine and finding it to be as clean as the day it was built. I've also heard people who always use only one brand say that they've found either sludge build-up, varnish, etc. on the inside of their engines when taken apart. I'm not sure I really buy the 'seal swell' argument, so are there any other opinions/comments? Thanks for taking the time to read this whole thing. I know this is a lengthy first question, but any thoughts would be greatly appreciated.