[JohnnyBrown]

I think the tradesman analogy is good, but the future programming career may have elements of the starving artist in it as well. Working for free to build a portfolio is a feature typical of creative trades that would be foreign to an architect or plumber.

[demallien]

Well, I don't know about plumbers, but architects know all about working for free to build a portfolio... For example, if an architect wants to do something a bit more challenging than yet another McMansion, they are going to have to enter competitions where only the winner gets paid. They do it anyhow, because placing well in a competition also helps to build your reputation as a designer.