Thoughts

I try to order subtopics by time to consider. The ideas presented will implicitly bias toward PhD for professorship.

“For some people, the joy of research is the joy of discovering something new that no one knew about. You might be discovering a new algorithm, a new operating system design idea, a new idea for maximizing the performance of disk arrays, etc.. For others, there’s the joy of truly understanding. You’ve probably noticed that in classes a professor or book will stop just when things are getting really interesting and say, “the rest is beyond the scope of this class.” In research, you can take a problem as far as you want and understand everything about it. For many, the joy of research comes from being able to make an impact – to change the way systems are built and design them in a smarter way. There’s also the joy of doing it right. In a company, the aim is to get a working product and ship it out quickly. In research, you can take your time and plan out your project so that you are proud to defend every one of your design decisions. Research is not about simple heuristics or quick hacks. Many people also relish the joy of being the authority on an area and of having their work read and cited by others.” [2]

Applicants with master's degrees are expected to have more publications and experience than undergraduate applicants. [1] [3]
When to start looking for recommenders: “as early as possible”. [1]
The process of application itself (especially customization) can help to re-evaluate fitness.

“Be really really clear why you’re doing the residency - the reason to do the residency/work is to do something you could not otherwise do at grad school/if you’re not sure about grad school.” [1]
If the only reason you are considering a residency is because you think that is an experience you will never get at a later time --- this is likely not true. [1]
Opportunities