Not sure if this off topic or not as I wear my skin every day . . .

After reading about many of you fab ladies' skin care programs, I decided to start using a serum in the morning and most evenings (the nights I don't fall asleep first!), and a BB cream in the morning. Previously, I had just used a moisturizer in the morning.

How does one know if they are working? How does one know if they should upgrade their products? (I went with Oil of Olay products as I could get them easily through Amazon, and they had versions for sensitive skin. I have allergies to a lot of dyes and fragrances used in cosmetics).