I think for certain things experience is critical but aptitude is just as important.  Only by experiencing certain kinds of failure do you get the right mindset for a lot of things in 'IT'.  I use the phrase "Not all things can be un-done; once you've made the cake you're never getting the eggs back" frequently at work with people that read the sales droid literature and think that a complex system is simple.  I believe people with the right aptitude can take to *NIX and other IT related fields easily; you can't teach most people attention to detail any more than you can teach some soft skills. 

I suppose for very simple servers - say a server that is JUST a samba server - you could probably get by with copying the config files to the new server if it's on the same version but I wouldn't want to manage an undocumented system like that; I wouldn't want to create that bus fact for the people using it either.