I started my first ICU NP position in 2004. At the time, my schedule was set-up in such a way that I was paired with a nurse practitioner for the first three months though I was technically still an orientee for a total of 6 months. It didn't always happen that way, the group was still in the process of building up our NP numbers so there were shifts where I was working with a resident instead of a fellow NP. It wasn't bad actually, there were quite a bit of stuff I learned from the residents too. Procedures were precepted by either an attending physician or an experienced NP until I got at least 5 (central lines, arterial lines, chest tubes, etc).
I would say it took me a year to get comfortable with the role and roughly that means knowing what the attendings prefer as far as patient management, knowing the pharmacy formulary as far as antibiotics and IV drip concentrations/standard dosing, knowing which ICU nurses I can rely on and which ones need more hand-holding, being able to set up my own procedure kits and doing procedures without anyone standing by for moral support, and being recognized by the other providers and staff in the hospital as a member of the ICU team.
When I moved out of state in 2009 and took a similar ICU position, my orientation was short and involved getting to know the hospital and the personnel I'm working with. It was expected that I am an experienced ICU NP. The transition was much easier.