Value-Based Fees: How to Charge—and Get—What You're Worth: A Guide for Consultants, Second Edition

6.2. CHOOSING TIME FRAMES AND CREATING REALISTIC EXPECTATIONS

Retainers are not ideal for very brief or very long durations unless they are periodically renewed, and even those relationships have problems caused by their longevity.

First, retainers that are too short don't give the buyer enough time to access your help under a variety of conditions, to allow truly valuable applications for your advice to arise, or to let you become adept at this particular arrangement with this particular buyer. I believe that the absolute minimum time frame for a retainer is a month, but two months is far better, and a quarter is ideal. For a single month, the buyer could encounter an event that usurps all of his or her time, and you might not be called on at all. (Even though you could choose to extend the retainer "on the house," it sets a bad precedent.)

Second, however, overly long retainers cause the buyer to question the value if you've become so successful at advising (and transferring your skills to the buyer) that toward the end of the arrangement there is much less contact and much less perceived value on the buyer's part.

I believe that the fairest retainers are probably for ninety-day periods, and they can renew at the end of that time on the same terms (if the client demurs but then wants to renew after the retainer is completed, you're perfectly justified in raising the retainer fee—that's why the sixty-day option is there—as part of the client's benefit). If you feel strongly about ...