I definitely wear 80% of my wardrobe 80% of the time -- within seasons. In other words, I live in a climate of extreme seasons so I can't possibly be wearing my summer things in winter.
But of my "within season" wardrobe, even playing favourites to a degree, I still wear 80% of what I own on a regular basis. I have what I would consider to be a medium sized wardrobe.
By "regular" I mean at least several times per month on average.