Two very good points here. WQilliamlayton hit the nail on the head, and bluecow provided addition input as to why ankle carry is not practical.
Many years ago I bought an ankle hoster and gave it a try, as Bill stated it is clumbsy, the holster never stays in place, it is uncomfortable and hard to get to if needed in a hurry. Along the same line, I have worn boots all my life, I thought an inside the boot holster would be great. I took a pair to my bootmaker and ask him to design and install a holster in the boot. It never did feel right, so we adjusted and put it on the outside of the boot. That never felt right either, I scraped the idea since I almost had to take my pants off to get to the gun.
As stated above, a small framed gun and inside the pocket carry has proven to be the best method I have found for most carry. When I can wear a coat I like a inside the pants holster for a large frame gun.
My best advice, try everything until you find what suits YOU best.