Serving size: A pea

Why: Serums are super concentrated products, so less is always more. King suggests simply tapping a tiny amount onto problem areas until absorbed into the skin.

Serving size: A blueberry

To avoid drying out the sensitive skin on your face, only apply a blueberry's worth of product to affected areas (the chin, nose or forehead) rather than the entire face.

Serving size: A rice grain per eye

Using too much product on the super sensitive skin around your eyes can cause irritation and puffiness -- the last thing you want. King suggests using your ring finger (the one with the gentlest touch) to dab the product from the outer corner in.

Serving size: A small red grape for a creamy product, blueberry for a gel product

This may seem like only enough for one cheek, but according to King, many of the physical scrubbers in exfoliants can be harsh on skin -- even if you're looking to slough of dead skin. These modest amounts are enough to get the job done.

Serving size: A rice grain

Drowning a pimple in a pool of product doesn't mean it'll heal faster -- it simply means you risk irritating surrounding skin (and wasting what little product is in that tiny tube).