Sure, but unless the shop is really top shelf, paying for a performance eval before service might or might not help. In your case, a spec check might have shown that the bleed filter wasn't up to specification (the usual reason for a piston replacement), or the tech might have known that the age of your model made it likely that the seat was captured (again requiring a piston). But most shops just aren't that good.
So that might have saved you $50, or you could have tossed the set.
Really, experience will tell you now.
You can skip the hose protectors. Regular service will just be (at your LDS) $25 per reg plus service kits.
So it's pretty common to have a $120-150 bill every service if you do all three.
But read and learn this:
Regulator Inspection and Checklist (Rev-8)
and buy an IP gauge. That, a tank of air and your kitchen sink (for regular rinsing after trips, and to check your second stage tuning) are all you need. This way, you can decide if you need service at the one, two or even three year interval. And there's nothing wrong with taking your seconds in for service while telling them to leave your first stage alone. But take them all in together so they can tune your seconds to the IP of your first.
