I think honesty is always the best policy – for many reasons. Not the least among them is that it's good for both you AND the client.

A few months ago I had a guy come to me who had just gotten approval for several million dollars in venture capital for his website that is sort of a membership rewards thing, and to make a long story short he said he was willing to pay me 60K to redesign the site and maintain it. At the time I was only beginning to learn web development, although I had been doing web design for some time. But I felt I had to be honest with him and let him know that I could certainly make the site look good, but he'd need to find a developer to build what I create.

In essence I knew I was turning away his business, because he could just as easily find someone who could do both the development AND the design. And I probably could have learned the development side to do what he needed (and as it turns out I have since then) but at the time I knew I couldn't and that if I set up a business relationship on a false pretense that I already had what he wanted, in the end we both would have been unhappy – likely me more than him, especially if it got ugly.

I've kept in touch with him, and now that I can offer what he wanted, I hope he'll still consider me since he hasn't found someone else. But either way I think honesty is always best.

Houses built on a firm foundation stand the test of time, but houses built on a cracked foundation fall with a great “THUD!”