When a business asks you to do something, compute your actual hourly before deciding if it’s worth it. It’s amazing how many times a month I get asked to work for less than minimum wage.
Today, for example, I got a request to do a tech review in trade for a copy of the book. Here’s my response:
Sorry, but I’m not interested in doing tech reviews for a copy of the book on a subject where I’m already an expert. Back in the 90s I got paid decent bank per-section to do tech reviews, I see no reason to work for less than minimum wage at this point in my career.