Antibiotics Save The Day??

In the future, if I have kids - I'm going to train their bodies to be strong - how? By NOT subjecting them to antibiotics for every little thing. I realise that that is such an important quality to have - to build up your body strong enough that it can easily fight off invading armies of germs whenever, whereever......How does one build up the immune system again after it's been wracked by antibiotics????