Apenwarr's take on Story Points

First, story points are abstract and unitless, which is a good thing:

People have all these weird hangups about goals and about time. Story points have the astonishing ability to just bypass all that. Nobody sets a “goal” that the project will take 5 points to complete. What does that even mean?⊕ (Pennarun 2017)

Next, story points are in deliberately coarse buckets of only fibonacci numbers, which cuts down on needless precision.

He then recommends a story point estimation strategy he calls “planning poker”

People all vote and then you see their results. If not everyone agrees, then the tradition is that you ask one of the people with the highest vote (the one who has spoken least recently), what they think is necessary in order to do the task. Then you ask one of the people with the lowest vote. Then, you discuss more if needed, or else go immediately to a revote, and you repeat until you all agree. As a shortcut, if the votes are split between two consecutive values, you can just pick the higher one of the two.⊕ (Pennarun 2017)