In the eight-character numerology, it is usually ten years of good luck, but why do many fortune tellers say it is five years of good luck, which one is right, please advise?

That's right. It is usually said that cadres and branches have been together for ten years, while the latter is five years in the sky and five years underground, and they have just separated.

This is still wrong. Generally speaking, in the first five years, we should look at the heavenly stems (70%), the earthly branches (30%), and the earthly branches (70%) and the heavenly stems (30%) in the second five years.