See https://www.nytimes.com/2017/08/07/business/dealbook/shown-the-door-older-workers-find-bias-hard-to-prove.html ... Note at the very end of the article, a LOT of POTENTIAL suits never do go to court... They are settled out of court "voluntarily" (meaning often by arbitration). In 2016, they EEOC collected $350 million for wrongly filed older employees, w/o the cases going to court.
Use link as above, or use search-string "Shown the Door, Older Workers Find Bias Hard to Prove". You often do NOT need to pay a ton of money to lawyers!