It is GREAT to do multiple mixes, but if the sound isn't right you're going to do more than you have to.
As far as the "perfect room", I never said there was such a thing. I'm just saying that real studios are built for this, and if you take a great mix from one studio to another, chances are it's still going to sound good...as opposed to having something that sounds great in the house, but shitty everywhere else.
About the headphones, it all depends on the cat mixing. Like I said, some cats can do it and it sounds official...some cats can't do it. Personally, I take my projects to real studios for mixing and mastering because I know I'm going to hear what I need to hear in that environment. But if I'm doing a quick mix for somebody at the house, the headphones do what I need them to do. I mainly focus on vocals and harmonies here, and they always have a nice crisp sound. If somebody wants the song mixed down and shit, I will refer them to a studio with good prices and a good sound because I'm not in the business of rippin' cats off and I know this isn't the spot for full on mix downs at this point.
Like I always say, to each his own. Some cats can have the best setup with the best monitors in the world, but they have no clue what they're doing. Some cats get by with barely any equipment but they are masters at their craft. It's all in how one hears and how that person soaks up what they are hearing...after that it's all in what they do with it.