Do you put face oil or serum first?

Excuse me, I'm just curious about your skincare routine. When you're applying facial products, do you typically use face oil or serum first? I've heard conflicting opinions on the matter, and I'm wondering what your thoughts are. Some people argue that oil should be applied first to lock in moisture, while others claim that serum should be applied first for better absorption. What's your take on the order of application? I'd love to hear your expert advice.