The Belief Desire Intention (BDI) agent paradigm provides a powerful basis for developing complex systems based on autonomous intelligent agents. These agents have, at any point in time, a set of intentions encoding the various tasks the agent is working on. Despite its importance, the problem of selecting which intention to progress at any point in time has received almost no attention and has been mostly left to the programmer to resolve in an application-dependent manner. In this paper, we implement and evaluate two domain-independent intention selection mechanisms based on the ideas of enablement checking and low coverage prioritisation. Through a battery of automatically generated synthetic tests and one real program, we compare these with the commonly used intention selection mechanisms of First-In-First-Out (FIFO) and Round Robin (RR). We found that enablement checking, which is incorporated into low coverage prioritisation, is never detrimental and provides substantial benefits when running vulnerable programs in dynamic environments. This is a significant finding as such a check can be readily applied to FIFO and RR, giving an extremely simple and effective mechanism to be added to existing BDI frameworks. In turn, low coverage prioritisation provides a significant further benefit.