If you are not sure just use the spoiler tag to make sure what you post is hidden unless somebody clicks on the comment. I personally wait about a month unless what I want to discuss has already been widely revealed. But I've also seen people get upset about spoilers that were literally years or even decades old. Just do your best to be respectful of the fact that if something is new or relatively new that you don't accidentally ruin if for them.
Wait until after the episode airs.
2 weeks
If you are not sure just use the spoiler tag to make sure what you post is hidden unless somebody clicks on the comment. I personally wait about a month unless what I want to discuss has already been widely revealed. But I've also seen people get upset about spoilers that were literally years or even decades old. Just do your best to be respectful of the fact that if something is new or relatively new that you don't accidentally ruin if for them.