Hi, my name is Alex and I live in Pasadena, California. I own a Mazda 3 2015. I wanted to know which is the best maintenance schedule and Oil change intervals for my car. I am open to suggestions. Thanks

 

Because you did not state your last service and what it was date and miles.......
I suggest that if you are not personally doing any of the service to look at your new Mazda service schedule and use that as your new and continued service scheduling.

Otherwise, it gets very complicated.
About the only service I recommend at 30k miles is a basic transmission pan and filter service. That one is not on the Mazda service scheduling.

You should also do more research on hundreds of responses to your question asked over the years about what you should do. It's all here on this forum and I am sure you know how to get around to find them .