If you worry at all about what could be creeping and eating your walls you really need to get a free home termite inspection so you can know for sure. That way if there is any problems you can address them immediately instead of waiting until the damage gets so bad that you can no longer repair it.
Not only will a free termite inspection tell you if you have termites now, it can also let you know where the weak points are and if you are doing anything that is making your home an easy target. Termite prevention is very important and knowing what you are doing wrong will help you correct it.
