Fruit cakes, the sort for celebrations, are usuallly made at least a few months in advance, it helps the cake to mature and the flavours all become richer and moister. My mother used to make wedding cakes as a additional income, and it was not unusual to have the cake baked at least 6 months in advance, but only marizpaned and iced shortly before the wedding itself. there was also the tradition of keeping the small top tier for the christening cake of the first child, I can can remember big wall cupboards from my childhood with lots of diffferent fruit cakes in all sorts of sizes with labels for many diffferent families.