Repairs has always been the most explosive of the 3 Rs at a dive shop...the other two are Rentals and Returns.
The scariest thing about this discussion, for a non-industry professional, has to be sorting out the excellent advice from the garbage. Obviously service is necessary on all regulators even if they are used infrequently and they should be checked annually at least. No manufacturer I know of recommends going more than 2 years for a rebuild service.
On the other hand, one good thing about a forum like this one, is it helps to identify some first class repair services, including the manufacturer's service department.
Like choosing a doctor, get a referral. Even good shops have turn over problems with service help, but the good shops get good training and know how valuable a good tech is and tend to keep them around.
If you only need your first and second stages serviced, you can remove the computer console and BC QD hose prior to the service. The shop does not need them to do the regulator work. (However you may want them checked out too. Many BCs now have alternate inflation regulators that will require the BC be brought in as well.) Write down a good description of what you do turn in on the repair work order. A good shop will do that for you and check to see that everything is not broken or missing when it comes in. (I like the photo suggestion.)
Lastly, I'd recommend learning a lot about your regulator so you'll know when it's amiss. Many of the biggest problems stem from the simplest mistakes, like not tightening hoses and retaining rings correctly... things you can check yourself. Visually check the mouthpieces and hoses to be sure they are in good shape. An IP gauge that connects to your BC QD hose can be pretty inexpensive to own and will tell much about what's going on internally.
Chad Carney
Zeagle FL Sales Rep.
Former 20+ year dive shop mgr.