I bought us both an iPad to share and discovered occasionally she uses it as a footwarmer once she's done watching videos. I've bought her slippers and heating pads but she never uses them.
I see her with both feet resting/standing on it while eating/on the toilet. I've taken a look at it and it's covered in grime from her foot sweat. I have to sanitise it before each use.
I confronted her and she said it's portable and big enough for her feet. Slippers and socks are too restrictive apparently.