Only you know your own skin and can rightly assess what it needs. But, I guess this is not always so.
In general, though, when they come out with new things, I take it that those new things have different formulations that addresses a particular (or multiple) skin need. In general, the new product is to replace what you are currently using. (This is my take.)
Anyway, I make my own routine. I rarely follow anyone else's skincare advice. It's all in understanding skin as an organ, and knowing which ingredients, and other things; i.e., non topicals, that helps a particular issue.