I've realized an irony with our Netflix usage: When we get a DVD that we really want to see, it usually gets watched and sent back on the same day it arrives. But, when we get a DVD that maybe only I want to see, or maybe neither of us ends up in a mood to see, we end up keeping it for a few days—sometimes for a whole week. We've yet to "declare defeat" on many choices and just send them back unwatched.
This is weird, when I think about it: It actually costs more money to hang onto the DVD—in a rentals-per-month sense—versus sending it right back and possibly requesting it again in the future when we're in a mood to see it. Of course, lots of back and forth with unwatched videos costs postage, but that's not our problem.
This seems like a sort of Zen of Netflix thing I should wrap my head around. And, if Netflix really wanted to save some money and exploit this bug of mine, they should recommend things that I kinda-but-don't-really want to see—so that I hang onto them longer and don't squeeze so much value out of my flat monthly rate.