put isolator switches on both batteries and there will be no need for doing it that often. When you put her to bed, make sure the batteries are topped off as well as possible, then as soon as you hit the store switch, also open the battery disconnects. Do it every time immediately when parking. your batteries, if in good shape to begin with, should last a few months at least.
but your problem now....it's almost certain that your batteries are not holding much of a charge, if any at all. Pulling them down too low causes some harm....pulling them down cold dead kills them fast in my experience.
If you're interested...I've seen lots of folks point to this resource for learning about battery systems. It does seem like a good and thorough resource to me....
The 12volt Side of Life (Part 1)