system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do helicopters have only four blades and not six or eight of them?
gpt
Some helicopters do have 6 blades, and some have as many as 12, split between 2 rotors. 

The reason for not having as many as possible is a question of weight and necessity. If your engine is capable of flying efficiently with 4, adding 2 more just adds weight, cost, and complexity.