I don't sleeve the cards and would buy a case if I had the opportunity. In case anyone is interested, I basically don't sleeve the cards because the effort of doing so does not match the benefits of game preserving. If I played so much so as to damage the cards in a noticeable way, I'd be happy to buy a new set of cards and the money was well spent.
If some store offered the service of sleeving them for me and the price was reasonable, I would do it. I understand it eases up shuffling, is that right?