That’s not to say that instant means bad, or ineffective — it’s just that any product that promises an instant improvement should be the cherry on top of your skin-care routine, not the cornerstone. And as for your skin "getting used to" something, I personally don’t buy it: If it works, why wouldn’t you stick with it? "It’s true that there is probably an optimal state that a product can get your skin to in terms of bacterial flora and pH, but by stopping, all you’re doing is taking yourself back to square one," Dr. Jack explains. "When you add that hero product back in again, it will work again, but only up to that previous point. It’s purely psychological to think it looks better after a break." It’s far better to keep using a product you know works for your skin, rather than swapping a handful of similar ones in and out for the sake of variety.