Is hanging or pumping a necessity

Are these two types of PE necessary to accomplish your goal size? Or do you think it can all be done by manual exercises?

How long will you continue to see gains from jelqing?

Just want to clear these things up. -SEYZ

Depends on the person and what/how their body responds to various exercises.

Some guys make gains using only manual stuff. Some guys stop responding and incorporate hanging/pumping and start making gains again.

In other words there is no general answer, only by trying will you know what works for you.