There should be a list of what staff members are required to do, and if they don't do it they lose their position. It should be as simple as that. If you can't perform the staff duties on a REGULAR day-to-day basis. I'm sorry but you shouldn't be staff. At all.
I understand temporary leaves or a busy day. But you guys make the site work, and if you aren't doing that then guess what? The site isn't working, and it's entirely YOUR fault. I see staff members on daily, and yet requests go ignored entirely.