[michjedi]

Books.

I read about 30-100 work-related books a year and have seen salary double every few years.

I try to alternate books between different areas, more or less from these sections:

Technical(on currently used technology)

Technical(unused tech vaguely related and may be useful)

Management

Domain(scientific textbooks, best to search from related university course reading lists)

Biographies/accounts/events of typical and super users

[lelele]

> I read about 30-100 work-related books a year and have seen salary double every few years.

Your salary didn't double because of books. I read a lot of work-related books, too, but my salary has been stagnant for years.