As most designers do I have been approached on a number of occasions to do spec work (nice way of saying free work). When I was first starting out in the industry I fell for this approach and was burned. It almost always starts the same way “Hey, would you be interested in doing a bit of work for me? The project has fantastic potential and the exposure for you will be amazing … and so on”. In short if the person pushing you to do free work has such faith in the potential of their project then why aren’t they willing to invest in it by paying you to do the work for them? The long and the short of it is, no other professional does work for free on the promise that it might lead to other paying work or exposure so why would designers? I should add one caveat to this, doing work for non-profits or charities that you support is a different story.
To learn more about Spec work and how it can/should be handled by Designers: https://www.rgd.ca/resources/no-spec
In conclusion I would like to share the below email exchange. Perhaps a little harsh but a humorous summary of the situation.