I've recently discovered GOAP and interested in implementing it for the AI in a game I'm developing. Something I'm stuck on at the moment, is determining when to plan. I've read through an MIT paper on it:
It mentions real-time planning and specifically:
The character follows this plan to completion, invalidation, or until another goal becomes more relevant
Should I then be planning every frame until a new plan is deemed better (lower cost)?
And if not, if I have multiple goals but pre-requisites for one goal are only met in the middle of a plan for another goal, when would be appropriate to re-evaluate?