Do you generally recommend that candidates go 'above and beyond' in preparing for interviews by? In which situations do you recommend this approach or not?

I think going "above and beyond" is a totally subjective thing; it is up to each individual what is above their baseline of preparation for an interview. But - here are a list of things I think are table stakes, that every PM candidate should do at a minimum to prepare:

• Know the company you're interviewing with: their main products/features, how they make money, how they differentiate from competition. If you're interviewing in a division of a very large company (eg. Amazon Logistics or AWS, both parts of Amazon), understand the same thing but for that division.
• Brush up on your past experience and how you speak to the impact you've had. I like to have at least 3-4 examples I can easily pull from, at the top of my memory, so I can quickly and confidently tailor a real story to a question that it makes sense to apply my example to.
• Get clear on what you're looking for in the role you're interviewing for - how you think you might be impactful, what the first 3-6-12 months may look like, etc.
• Get clear on what you're looking for in the interviewers - any red flags to watch out for in how they ask questions or react, what questions you'd want to ask them about the role/company/etc.

I basically recommend these 4 things in every situation, at least.

One should prepare for an interview, especially if its a job that one is very interested in. While preparation is something one should give 100%, one should not over do too. I would rather prepare for questions like what are situations where one went above and beyond in their careers.