There's a split in the law (even in the USPTO) on whether a lawyer who calendars or sends maintenance fee reminders creates an on-going attorney-client relationship with the recipient/patent owner. This is highly significant since, for example, a lawyer who represents a client cannot be adverse to it, at all, and "adversity" has a very unwieldy definition in all areas, but especially patent practice. (In addition, in some states an on-going attorney-client relationship tolls the running of the statute of limitations.)
So, what do you think of this language, for an engagement letter, say, to help avoid misunderstanding?
"If a patent is granted to you as a result of our prosecution, you must periodically pay maintenance fees or the patent will lapse, perhaps rendering it worthless. Generally, fees will be due 3½, 7½, and 11½ years after the date of issuance. We will send to your last known address maintenance fee reminders as a service, even though our attorney-client relationship has concluded, but only if you request us in writing to do so when we forward any patent to you. If you do not ask us in writing to do so, we strongly suggest that you either hire a commercial service to do this for you, or place reminders of maintenance fees in more than one calendaring system. Failure to docket maintenance fees can result in the loss of patent rights."