Meh, I know I am anecdata, but I don't use them that much, maybe once every 6 months for a book or something. I know some people use them every day, but I just don't and don't really ever see myself doing so. I mean, it just isn't hard at all to pick up the stuff I need/want from the store on the way home*

*Caveat: I live in the suburbs of a larger-ish city, not in the rural areas of the world.