You actually did miss quite a few options, but to answer your question, I have only had one person on official contract as my slave. I dismissed her, sadly. However, I have had many play partners over the years as well as partners and lovers. As of right now, I have two play partners and many others who serve me randomly when I am out and about. I do not ask for it or request it, but s-types will come to me and ask to prepare my tea or coffee, so why refuse?
Contracting someone is incredibly different from being a play partner. I can put a whip or flogger to a body and not have any desire to be served by that person. The two are very separate. The way that I play with what's mine as opposed to how I play with what is not is worlds apart.
I have no interest in having someone care for my leathers, however, unless they are serving me. They do not need to be under contract, as that is something that I do when D/s has already reached a certain point, but they do need to belong to me as my girl or boy.