Do you know, what the checkbox "sage" actually does?
You should, if you took the time to read the FAQ. It is explained there very well.
https://guro.cx/faq/
Checking the box just enters "sage" into the E-mail field for you, if you're too tired or lazy to type it yourself. 🥱

>Typing sage into the email field prevents the thread from being bumped. This is used when you are not posting something that portrays to the topic of the thread.

While posting a comment or remark, take a moment to think if it is important or interesting enough to bring the thread to the top of the board. If not, use sage!
On the other hand, if you are posting an image or video, you probably want others to see it. Do not use sage in these cases.