Should I work for free?
This chart was published by Jessica Hische two years ago and it is a useful reminder of the reasons why you shouldn’t work for free, except if the work is for your mum, of course. Always do stuff for free for your mum.
Should I work for free? by Jessica Hische
It was made by a designer, but it is applicable to all creative/intellectual workers. Really, please: stop working for free. Work for yourself instead.