”When you can”, is nothing I disagree with, but also bad advice in that it doesn’t give any criteria.
For example: if you are writing the parser for a compiler you will spend years on, then a handwritten parser is great! You can tweak error handling easily and do all sorts of things in an easy to read and understand manner.
If you are writing a tool that will take some code and transform or analyse it in some way which isn’t a full-blown compiler, then a parser generator is nice to focus on the actual meat of the problem.
