When should I replace it bicycle chain

Before we replace the chain, we need to find out when to replace it.
Details are provided on how and why they should be replaced.
I tried not to be bored as much as possible for the viewers, but it's not enough yet.ᅲ
However, I always thank the subscribers for watching. ^^
If you have any questions, feel free to leave a comment.
I'll give you an answer. ^^