We're in the process of taking over the IT management for a medium-sized client. They have been working with another consulting company, located in a city a couple of hours away, and this transition process inspired me to write a quick article about what information your consultants have that you should have also.
It's your system - you should have the administrative passwords for it. We too-often see systems where the outsourced consultants have and maintain all of the administrative passwords and don't share those with any responsible parties at the client. Our present transition has been slowed because only the outgoing consultants have the administrative passwords and they've been slow to share them. They are, at least, resetting those passwords and promise to give us the new passwords shortly.
It's not hard to imagine a less-cordial handoff though where the outgoing folks might refuse to provide those passwords or choose to hold those passwords "hostage" pending resolution of issues real or imagined.
It's your system. You should always have administrative passwords for it.
Diagrams and Documentation
Transitioning to a new support provider is a lot harder when the new provider has to figure out where everything goes. At the very least you should have a wiring diagram that shows the basics of how your system is cabled.
Your support provider should also be able to provide you with at least a basic inventory of what your systems are, what they do and where they're located.
Don't be in the dark. Even if you're not planning to switch providers anytime soon, you should have that basic information about your own systems on file. If you don't have them...ask your current provider for copies that you can put away somewhere safe.