I have a pair of stiletto type high heels (but not crazy high) which I have not worn for a while. They are very good quality italian ones and one of the reasons I bought them was that they felt really comfortable and stable.
Just tried them on tonight after not wearing for a while and they feel a little wobbly - look perfectly ok but I can feel a little wobble. And I promise I haven't been drinking! 
Do they usually get like that after a while?