Google Webmaster Tools. How often do they update backlinks?

Guessing that Google Webmaster Tools is the best place to check for backlinks.

Two questions:
1. How often do they update?
2. Is this a complete list?

Sorry a third question immediately popped up
3. Do they include nofollow links?

Guess it's not too difficult to test Q1 and Q3 at least - Has anyone done that?

 

Here you can find the answer of most of your questions. http://googlewebmastercentral.blogspot.com/