I HAVE ONE SMALL GLASS AND A LIMITED REGISTER

I keep a word bank in reserve to answer people when I am not listening. The problem is that I am always listening. I never break into the reserve. Whether this is really a problem, I am not certain. I am certain there is a problem with my reserve. I break into it sometimes just to check in. To make sure everything is still there, I open it up. I think that I am opening. One cannot be certain.