Timing belts are usually maintenance free. Rule of thumb: when buying a car and there's no mention of timing belt replacement, have it replaced alongside drive belts (as well as the tensioner, cam seals, etc).
The SA told me that I should've replaced it at 100k kms. What are the things that I still need to replace when changing timing belts? My SA only told me timing belt and tensioner bearing. I don't recall him telling me about cam seals.