What is trading up and trading down?

when there became the marketing concept or evolution of marketing this concept has been added to the marketing department. this is also a new technique to aware once more your customers that your product is available in the market. inaddition we can say that trading up and trading down is tactic toimprove your market share .also the meaning of trading up and trading down means to discover a product to help your other products to be a high share in the market. # #