It is what it is, painting unseen areas,or any other areas that may or may not be seen, taking no chance they may be seen unpainted. And , no we don't "tear the models apart" the models.
Let me just point out, as a judge in many model contest, seeing an unpainted area will detract. many times a tie breaker. Unpainted under hoods not withstanding.
and yet, we still have a very healthy NASCAR thread on this very board. http://www.modelcarsmag.com/forums/index.php?showforum=32 and there just buildin' away.
I use a roll top desk. Somewhat limited bench space ,you gotta keep the projects to a minimum. But you can sit and the drawer space is nice. Depending on your available ca$h and space there are many to chose from. and the top rolls down to hide the mess.