Jewelry Question

Hello beautiful people, I have a little question about jewelry. I need to know if there are any accessories or jewelry that are necessary for an outfit, like I know there should be headwear of some kind but should a Lolita always wear and necklace and if so what kind. I realize that the answer would vary based on the outfit, anything OTT would require more everything but is there anything necessary regardless? I looked through the memories and tried the wonderful world of Google but I am still wondering.