Estimations have always been a big topic, especially in the Software Engineering discipline. Independent of the method you use (such as waterfall / agile) or field you are in you will always need estimations.
In this post I try to analyse some of the Agile estimation techniques in two layers (the batteries in the drawing): how accurate (or precise) is the technique and how fast the technique can be applied.
Having a definition of both layers will always depend on your company and team style and needs. Some companies might be totally fine with 'No Estimation' techniques while others might need roadmaps or timelines which would require some more precise technique.
Check out the infographic:
My favorites are T-Shirt sizes or No Estimations, but there is many more such as Dot Voting or Affinity Mapping. Which agile estimation technique are your teams using? Would you agree with the layers presented?