Expertise is like love

[...] The conclusions many advisors draw are that they must be careful about "giving away the store"... The truth is, expertise is like love: not only it is unlimited, you destroy it only by not giving it away. Love for a child is not cut in half with the birth of a second child. And expertise is not to be confused with what can be scanned into a database. The human capacity for problem redefinition and cretivity is what a successful advisor brings to every situation. It is unlimited; it only gets better with practice.

['The Trusted Advisor', David Maister]