I wouldn't agree that actors and musicians have shorter life on the "market". There is plenty of examples that it is not the case. As for computing market - I

I wouldn't agree that actors and musicians have shorter life on the "market". There is plenty of examples that it is not the case. As for computing market - I was recently working with a database designer who was in his 70s. He graduated with a mathematics degree a few decades ago and had a really impressive portfolio of companies and people he worked with. Even though he retired a few years earlier, he simply refused to stop building things. We couldn't ask him to work with us until 6am or learn jQuery in one night but he brought a lot of value to the project.