Generation IV External Engine - re-using gaskets OK?

I know the book says to never reuse gaskets, but is this really necessary?
The LSx gaskets look like they should be reusable.
Not trying to be cheap, just not wasteful.
I have reused water pump gaskets as well as intake wo problems.
Is the factory just being ultraconservative or perhaps its part of a business model selling more gaskets?

It depends what gaskets you are reusing. Most cases the shadetree and weekend mechanic will be fine reusing the easy to get to gaskets, but some of them like the oil pan, rear cover, etc I would not even consider using again because if it leaks it's going to be a huge pain to replace. I would hope that no shop reuses any gaskets on a customer's car though, because a customer shouldn't have to suffer the inconvenience of bringing it back if a reused gasket leaks.