I guess it depends on your technique. I'm original owner and sole mechanic at 180k and my throttle body has never been off the engine. I clean in place every 30k and I'm happy at how it looks when I'm done. I am careful not to let stuff get into the IAC. THAT I have never cleaned. The FSM says not to so I don't. So far, so good. Doing the TB every 30k it never looks that dirty anyway so I don't make much of a mess. Never had an idling issue not due to something I failed to reconnect.
Not saying you are wrong to do it; just that there is more than one way to skin a cat.