Is there any difference between brands?
Short answer: Yes, some bottles are green, some are blue, some are black, etc.
Long answer: Most oils are made using nearly identical processes, and variations between the final products will be indistinguishable.
There are essentially four domestic motor oil producing companies, Exxon/Mobil, BP, Shell, and Valvoline. Almost any other labels you see are just brands owned by one of those four.
And with oil refining being a relatively old technology, you can bet all four have arrived at more or less the same point in its evolution and are cranking out nearly identical products.
If you want to save a few extra dollars and earn some credibility with your local parts store’s staff, pass by the big brands, with their talking cartoon spokescars and such, and grab a jumbo bottle of the store brand.
That bottle is filled with the exact same contents as one next to it selling for $6 more, and if you’re lucky, someone in the store will tell you exactly which one. The same goes for all auto parts store branded fluids. You’re welcome.
How often do I REALLY need to change my oil?
Of course the number we are used to hearing is every 3,000 miles. That might make oil companies happy, and would have been good advice in 1979.
Again, the best source for an answer to this question can be found in your owner’s manual. You may be shocked to see a recommendation for a 5,000 or 10,000 mile interval.
If you happen to have a Jaguar or two in the garage, you can wait 15,000 miles.
But whether or not you are doing it yourself or having someone else change your oil, hopefully you are now armed with a little more knowledge than you had a few minutes ago.