So where should the tubes be?

Source, preamp, dac, amp? Or should they be in as many components as possible? Does anyone subscribe to such a system where there are tubes everywhere?  Base answer on acceptance of tubes somewhere.

"I was just busting your balls as the term “mate” is often used to describe the activity that results in producing offspring. Matching is a more political correct term"

Politically correct thats funny to me. I however stand by my terminology...mate... 
If you do it wrong your still screwed , right?