Skin prep does not photograph as dramatically as a lip color or an eye palette, which is exactly why it gets skipped first when a routine runs short on time — and exactly why skipping it shows the most by midday. A base applied over dry or uneven skin has nothing stable to hold onto; it creases, patches, and fades unevenly no matter how good the formula is.
A lightweight serum from Skin Prep, worn a few minutes before base, gives everything that follows a smoother surface to grip. The difference is not in how the makeup looks in the first ten minutes — it is in how it looks eight hours later, at the end of the day it was actually worn for.
Treat skin prep as the first product in the routine, not an optional add-on, and the rest of the edit performs the way it was formulated to.