There’s nothing quite like the bliss of introducing a new ingredient or formula to your routine that does the work—like, Did you just get a facial? sort of work. You gladly restock, tell all your friends about your gold mine find, and wake up each morning to an impossibly lit-from-within glow—until one day, you don’t. Over time, that once brilliant glow has dwindled down to a flicker; your skin isn’t worse, per se, but it’s not as lustrous as your initial memory serves.