What role do your personal skincare essentials play in your skincare routine?

When it comes to skincare, there's always one product you feel you absolutely need. So, I was curious about how you define your personal skincare essentials. Are there any daily essentials that have become your go-to products? Or are there specific skincare essentials that you only reach for when you have a specific concern? My routine is fairly simple, but I find myself adding new products based on my skin type. If you have a favorite skincare product that you consistently use and are satisfied with, please share what makes you stick with it.