The question: At what level does each class get its subclass?
When building a multi-classed character for a one-shot I wanted to know when each class receives its subclass, since subclasses provide a lot of personality and power to characters. Searching the internet found a lot of people asking the same question on various sites, clearly a common question.
However the answers were all partial, wrong, or presented poorly making them unsuitable. I checked this site but unfortunately it hadn't been asked here as far as I could see.
I created a question and self answered it as clearly as possible with the pertinent commentary about which classes are unusual.
This question was closed because the question could be answered by reading the rule book. This is however not a hard and fast rule, at least in the 5e sub-community, as the vast majority of questions receive answers from the rulebook. On the front page for example is a highly analogous question asking which PC races do not speak common, which is answered simply by checking the rule book and looking at each race. Many high rep users and moderators have interacted with this question - a moderator even answered the question.
I'm looking for a way to preserve this valuable Q&A for myself and others and hopefully understanding this new rule.