If you need to reflect on learning from something way more lengthy than, say, a two-week sprint you will benefit from doing a more detailed and thorough retrospective.
This board helps you and your participants to first describe and recall your reality using timelines and focus areas. It also offers tools to really get to the bottom of the things you want to learn from and finally collect ideas and actions for how to move on.
Any project manager, coach, or line manager should gather your group after a lengthy achievement to learn, regardless if you do bi-weekly retrospectives or not. This will help you deal with larger obstacles and find systematic issues you might miss when just looking at the past two weeks.