What I would say is that hiring consultants can provide value for money. There are many cases where you need a specialized expertise for a short period of time, and it simply makes more sense to acquire as much of it as you need rather than to try to put someone on staff permanently who may be underutilized. That, to me, is the prime example of when using a consultant is appropriate, when the specialized expertise and the service are only going to be required for a relatively short period of time.
On November 23rd, 2009. See this statement in context.