A battery conditioner is an excellent idea, but I'm not organised enough to remember to plug it in if I'm not planning to use the car for a week or two.
But the good thing about the CTEK (and other good quality conditioners) is that they are well able to top up your battery charge in a few hours, so I tend to plug mine in if I'm planning to use the car the next day and I haven't driven it for a while.
