I am considering purchasing a used watch from a high-end manufacturer, like Patek Philppe, Audemars Piguet, or Vacheron Constantin. I am looking in the < 5k price range. I would like something mechanical with a leather strap and a relatively simple design. It looks like, in this price range, that I am looking at a manual wind as opposed to automatic. Is this a bad idea? Is there anything I should look out for, or any other manufacturers I should consider? Thanks ETA: I am seeing a lot of these watches on ebay with either new or custom cases. Should I avoid these?