Deprecation is a necessary function for the health and innovation of the web ecosystem. However, web feature deprecation is an understudied topic. While Chrome has a protocol for web feature deprecation, much of this process is based on a mix of few metrics and intuition. In this paper, we analyze web feature deprecations, in an attempt to improve this process. First, we produce a taxonomy of reasons why developers want to deprecate web features. We then provide a set of guidelines for deciding when it is safe to deprecate a web feature and a methodology for approaching the question of whether to deprecate a web feature. Finally, we provide a tool that helps determine whether a web feature meets these guidelines for deprecation. We also discuss the challenges faced during this process.