I love the gecko caves. My leos love them as moist hides with moss inside, and i love them because they are so easy to clean thanks to the top half lifting off so easily. This also makes it easy to check on a stubborn/shy gecko who doesn't want to come out.
previously had a medium one but my leopard gecko is possibly a giant morph and was grtting a bit too big! She would still squish herself into the medium one but thought it was time for an upgrade. My only issue is that the large is quite a lot bigger than medium, I wish there was an in between size as it does take up quite a bit of space. She's getting a tank upgrade soon so not the biggest of issues but still.
A medium would probably be big enough for a smaller female leopard gecko around 7.5 inches long, my female is 9.5 just for reference :)