"The life of a software architect is a long and rapid succession of suboptimal design decisions taken partly in the dark."The purpose of this paper is to shed some light on the darkness, by discussing a key characteristic of successful software architectures - the use of reusable assets. Reusable assets provide a valuable vehicle for capitalizing on the work of other successful architects, from fine-grained programming idioms to large-grained off-the-shelf packaged solutions.However, consideration of reusable assets can itself be a minefield. There are many different types of asset to consider, and it is not always clear what is meant by each of them, and the value they provide. What is the difference between an architectural style and a reference architecture? How does a mechanism differ from a framework? The purpose of this paper is to discuss the different types of reusable asset available to the architect, their characteristics, and their usage.