A hammer just popped up for sale and my wife says I need it. I will probably have to sell some stuff, but how many hammers is apropriate??? I have two running hammers at the moment, and I have two huge foundations available....

You need as many as you have room for in my estimation.

I thought you meant hand hammers haha. I guess the same rules apply for power hammers as for hand hammers. As many as you can fit in the space and still use it. 

Pnut

 

When I am in production I will have different tooling on each hammer. When I am in regular mode, I will still move between my Bull Air Hammer which is great for tooling and my Beaudry mechanical for speed of drawing. The work is what drives the need. When I had one hammer I still got a lot done and just had to allow for changing dies. Having an easy way to switch tooling might be a bigger time saver than the extra hammer.  I am making this point more to beginners who think that hammer quantity is more important than shop setup and clever tooling. Getting your first hammer is a quantum leap in improved production capacity. After that it becomes more of business question or for the hobbyist maybe more of a want than a need.

It never hurts to have a spare or two, in case of break down and having to make or buy parts. Each hammer will have a distinct personality too.

You can never have too many hammers. 

    I agree. but will spare you the other racks pictures.