I have clients in several industries. I know – I should concentrate on just one. But I just can’t. It’s a personality flaw.
That said, I create documents and books for my clients, or clients I want to attract. I do that across industries. If I had to write content for each industry, I’d never get any other work done.
I have a rule I use with the karate students I teach. “Mr. Gardner’s first rule of karate: cheat whenever possible.” By this, I mean use the things and people that are around you to get yourself right. The same thing goes for content. If you create it once, modify it and use it again.