How do people end up chipping the tenjin?

It looks common and I wonder what steps I can take to avoid chipping it. I know there are caps made for them, but I also read on another thread here that drastic changes in temperature and/or humidity also come into play. Is it possible to rub some sort of oil on the wood to cope with such changes in climate? Also, when it comes to the skin, how would you go about rupture prevention during travel?