We recommend a programming construct - availability check - for programs that need to automatically adjust to presence or absence of segments of code. The idea is to check the existence of a valid definition before a function call is invoked. The syntax is that of a simple 'if' statement. The vision is to enable customization of application functionality through addition or removal of optional components, but without requiring complete re-building. Focus is on C-like compiled procedural languages and UNIX-based systems. Essentially, our approach attempts to combine the flexibility of dynamic libraries with the usability of utility (dependency) libraries. We outline the benefits over prevalent strategies mainly in terms of development complexity, crudely measured as lesser lines of code. We also allude to performance and flexibility facets. A Preliminary implementation and figures from early experimental evaluation are presented.