Adding subcategories later
My site isn't up yet but I was working on having 12 categories. It occurred to me that I may get over 100 ads in a category and might then have to have subcategories splitting them into smaller groups alphabetically - A-G, H-N, etc, to make it look tidier. However I don't want to launch the site with those sub-categories because until all the ads are posted it will look a bit pathetic with only 1or 2 in each sub-category.
Can I add the sub-categorues at a later date, or will I then have to re-post each ad manually? Or should I set up the sub-categories at the beginning, if there is a way to hide them until the volume of ads gets high enough to need them?
What's the most practical solution?