system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Are signatures a legal thing?

Could i just go my whole life alternating between different signatures or do i have to stick with one particular one?
gpt
Signature has no inherit legal power in the US. It is not even required for a contract to be valid. However, it is commonly used for evidentiary purposes in a dispute to show you authorized the action. 

You may change your signature at any time or use multiple signatures concurrently. The latter is rare, but recommended under certain circumstances. Just remember, a mismatching signature is a strong indication of fraud... for all potential parties, including you.