https://www.nytimes.com/2019/09/23/business/ageism-advertising-aarp.html
In this part of the country, in tech, ageism seems to kick in hard at about 35.
AGEISM
Just the weekend before last I read "Essays after Eighty" by Donald Hall (former poet laureate of the US). It's worth a read, but a couple bits are cringeworthy, like when the docent in a museum talks to him in high voice with kiddie words as if he might be struggling to understand that these are paintings. Hall decides not to tell the docent that he wrote an entire book about the painter in question.