[@Izurich]

For the question on actual knowledge, I would say you would at least need to know basic concepts of your character's field, but it's not like im going to quiz you or anything. Whatever you have/are willing to learn about your characters field of study should be fine.

Referring to hypothetical max/min ages, I would say 18-60 for ages.

As for how I handle various LMs, I will usually do extensive research on the topic and compare it against that. (Unless it's ADHD, then I compare it to myself and my family) It will however come down to how well one can describe and stick with the tendencies of the neuro-divergency.