If you haven't seen Dan Hull's insights in the form of "12 Rules" for operating his firm, they are a worthy read. He just posted Rule 8: Think Like The Client--Help Control Costs.
I agree with Dan that those you serve appreciate when you advise them to pursue the best course of action for them, even when it means less money for you. These excellent principles demonstrate your worthiness of their trust as a long-term advisor.
He gives an example and I can, too. There are many instances in my own practices where I've advised customers, or even prospects, that they don't need my help on an issue, that what they are doing is fine and good. This raises eyebrows in an appreciative way and it also increases future opportunities with them because they know I'm not just out to sell them whatever I can--I really am looking out for their best interests.
I am also particularly fond of Rule 6: When You Work, You Are Marketing in which Dan says:
So we are always marketing--and in [providing services, we are] constantly sending to clients barrages of small but powerful ads.
The ads range from "don't hire us again" to "we want to keep your business--and get more of it".
Very, very true. I've previously referred to these as "moments of truth" but I really like Dan's description--it really brings his point home.