'Rank checking' has far less value to me now than it ever has, and will have even less in the future I think.
'Personalized search', 'regional results', 'flat line' capping of traffic etc.... have all played their part in making it increasingly difficult to trust that the client, his potential visitors, and 'we' are all seeing the same results. It has also given us some welcome leverage in convincing our clients of the need to switch to other metrics to measure performance.
We check sales and site visitors, and react if we see something unexpected happen there - rank checking is what we do as one of the steps of 'reacting'.
I fully understand why some people need to use to keep clients happy, and understand it does still have some uses, but I prefer to try and train clients to focus on the metrics that really matter. I would rather have an easy life and less money than be 'rolling in it' and have to listen to another t**t of a client ring us up at 8.58am complaining that he is no longer #3 for a phrase that his MD thinks is important but has actually made f**k all sales in the last 2 years.
If I was motivated to get, and keep, the larger more lucrative clients, I would obviously need to change my tune... but s*d them, they just get in the way of having fun