Does the tooth need to be sanded down for a bonding? (photo)

I have a small chip on my front tooth. I asked my dentist about getting it fixed and he said he would need to remove a part of my natural tooth that is much larger than my chip. Is this true? From looking at youtube videos, it seems like there's no prep needed at all. Can you do this without prep? I'm not so much worried about redoing this every 6 months as much as doing the least invasive thing possible. Is it also true that every time you replace composite, even more natural tooth shaved off?