I have a 2010 GX and recently replaced the battery (less than a year ago).
I ended up buying a 2013 GS and had the old car parked in the driveway for about 2 months. I went to start it and the battery was almost dead. I boosted the battery and it started no problem. I took it for a spin and it was fine with no problems. I started it again about 2 weeks later and it started no problem.
2 weeks after that I went to start it again and it was completely dead. I boosted it again and let it run for about 15 minutes then took it for a spin. While driving it around the block, the steering was sluggish and every time I made a turn I noticed that the headlights would dim and the steering would be sluggish. The next day the battery was dead again.
When I drove the car daily there was never an issue with the battery or electrical system.
Is this a battery issue ? Or is there a problem with the electrical system ?