Initially I was plugging in every time I came home too, but now I try to just plug in on my last return, not for any particularly good reason. Well, I tell myself that the fewer times I plug in, the less wear on the port and the charger, but then again, I've been encouraging my little kids to the plugging/unplugging for me, so that probably negates any effort I've made on that end. I'm using the trickle charger, and those bad boys seems very expensive to replace right now, which I think is weird since my understanding is that the actual charger itself is built into the car.
I've forgotten to charge overnight twice. Once, it made no difference, I had plenty of battery left for the next day as well as getting it charged fully after that. However, the other time, we had planned an outing of 80 miles roundtrip, and while we started out with just over 80 miles on the guess-o-meter, this was mostly highway traffic, so we clearly weren't going to make it all of the way back home. So we stopped at a dealership, let it charge for a half hour, and enjoyed some frostys next door. I though it worked out just fine, but DW was still upset with me.