When you should zap a post?

• you want that post to be more visible on SN top, so others can read it faster or don't miss it.
• you received from that post something valuable for you

When you should NOT zap a post?

• is a repeated link, without any explanation
• is a user that you know and/or appreciate and you just zap instinctively all his posts/comments. Wrong, zap only if is really necessary and that post bring YOU value.
• is a shitcoiner. See their bio or posts history. It's quite easy to find them, they always reveal themselves.
• assmilkers trying to fool others for few sats