Battery Life Usage Question For Netbook

I have a netbook by Dell which I really like. I use it mostly for reading in bed. I like to browse the Internet wirelessly.

But my bed is far from an outlet so I use the netbook battery. I usually only use it for less than an hour at night, and then I recharge it during the next day.

But in terms of the life of the battery would it be better to just buy a long extension cord. Also what does it mean in terms of recharging the battery. The battery never runs down much