I ordered my usually size as I am a solid size 10 in all shoes. At first I thought they might be too small cause it was a little difficult to get my feet in. I had to slide my foot as far into the toe box as I could to slide the back up onto my heel. I think the design of the back being made to be folded down makes the shoe a little harder to get into. Usually with slip-ons I can just slide my foot in and wiggle a little to push into the heel. The softer back of these make it so I have to pull them up instead. I thought that this extra effort might be annoying, but it's really not because they are so comfortable! What I thought was tightness at first was really the shoe hugging my foot like a glove. The lining is incredibly soft and hasn't caused any hotspots after walking in them with no socks for a week on vacation. There was pretty much no break-in period either. I wore them around the house for a few hours when I first got them, then took a chance on taking them on vacation and I was really glad I did! I love these so much that I'm planning on buying more colors.