You can do the same a moderator does without committing to the staff position, I always say.
This is why I will never apply for moderator again, because there is no need for it. I do not intend to commit to the position, nor think it is necessary, redundant, because one way or another you can strive to help in the same or similar ways.
People just don't think about this, and think being a moderator only means having a red name. But that not it at all: Being a moderator is knowing the rules, knowing how to help people, and choosing the best decisions for the community; not just having some red name.