This is an old-age question. The question is even more complex today because many moisturizers claim to do more than moisturize. From sunblocking to peeling dead skin cells, today’s moisturizers come with bells and whistles that a simple-minded drug store lotion cannot emulate.

Sisley’s Emulsion Ecologique costs hundreds of dollars, while an equivalent amount of Lubriderm costs less than $10 and both relieve dry skin. So will cooking oil, but who wants to smell like food?

Price is certainly closely tied to the aesthetics of a moisturizer’s packaging, fragrance and marketing message. Who’s to say that the effect they produce on our psyche isn’t as important as their formulation?

On the upside, products that fail to produce any results over time eventually fade from cosmetics counters.

One last factor is personal preferences for particular textures and fragrances. Given comparable performance levels, there’s no qualitative measure that can explain why one brand is preferred over another.