After I got my second automated message from Blockbutter to return a DVD I had already returned to avoid a late fee, I gave up renting.

Now I just buy used DVD's online. Most of the time the prices are pretty good, since BluRay and online are moving to take over the DVD market. 

Sure you are taking a bit of a chance buying used online, like the guy that sent me the empty DVD box with a note that said "Sorry this is how I got it when I ordered it online." !