Web caches are a software answer to the growing demand of bandwidth on the Internet. But the increasing number of dynamic Web objects like Web services decreases caches performances. This paper proposes to adapt dynamically caches to the cached objects. The required adaption is often dynamic, motivated by a variability that programmers could not anticipate before runtime. This paper discusses the possibility to use aspect orientation to achieve dynamic adaptation. While aspects are appearing as a suitable tool, dynamic adaptation adds some requirements to the aspect system that could be used. The purpose of this paper is to reach a clear and explicit understanding of these requirements.