2019 YDI – homework question

As we are completing brainstorming for Q1 & preparing our quarterly actions / fails, should we just prepare Q1 now, and then as were approaching subsequent quarters, do new brainstorming to create new actions / fails based on where we are / what we have learned during Q1? Or is the full year plan something we should create now and stick with / adjust later? Regardless, clearly if we are following our 2019 goal plan, we will be completing this work throughout 2019, along side of the daily work for each coming month!