My experience is that to avoid calcification, you should move between projects/companies. You won't do the same thing for too long, even on the same OS/language

My experience is that to avoid calcification, you should move between projects/companies. You won't do the same thing for too long, even on the same OS/language combination. The danger, in my [bitter] experience, is to stay in one place with lots of other people that also stay in one place. Since you mentioned Perl -- it is an old hobby (and present job; hired/paid as a senior, feels like a junior with the new stuff), I'll use that as an example. Perl is a totally different world now, compared to just a decade ago. Testing took over completely, about then. The testing support is really good. (See CPAN + Perl testers; please copy that in other environments.) The use of the language ("Modern Perl") is totally different -- see e.g. (not only Moose and the language extensions but the ability to create them!) http://search.cpan.org/~flora/MooseX-Declare-0.35/lib/MooseX/Declare.pm http://search.cpan.org/~flora/MooseX-Declare-0.35/lib/MooseX... Many of the work domains (e.g. web development) are also very different. And so on. (AFAIK, it is similar in most other scripting languages.)