As the primary dish-washer in my house, I have a tendency to reuse dishes and silverware.  I won't reuse anything that looks/smells gross or has any hardened food on it, but I'll usually do my best to use a plate more than once and a cup as long as possible.  The way I see it, my actions will have at least 3 benefits:  (1) I'll have to do less dishes; (2) I'll use less water and electricity; (3) I'll feel good because of (1) and (2).  I developed this tendency in the brief time I lived by myself.  I didn't have many dishes to begin with, so I had to stretch out their use as long as possible.  I basically had two sets of plates and cups:  The set I was using, and the set I wasn't using.  So to minimize time spent on frivolous tasks (like washing dishes) and maximize my available resources, I'd reuse my dishes over and over again.  And since I lived by myself, no one knew about it but me.