Don't size down if you're a full size
I'm a size 8 and I ordered a size 8, thankfully, these fit perfectly. I can use it with or without thick socks and still feel comfortable. There's room in the toebox without the shoes being too big. I honestly don't think I even need to break them in. If you're a half size, then i recommend sizing down because sizing up would be too big for your feet, though you'd probably need to break these in.