A colleague elsewhere asks on Facebook (with permission to repost the question here):
What are one's duties with respect to being an external reviewer for promotions? They are a TON of work. How often and under what circumstances do I need to say 'yes'? I just got a request and if I say 'yes' it will be the third I do this season. Is that low? High? I need help here! I know how to self-moderate appropriately when it comes to referee requests, but I have no sense of the industry standard on this...
We touched on some aspects of this several years ago, but it's worth airing again, especially since some new issues are raised here. Thoughts from readers? Signed comments strongly preferred.