Considering the big red S on the side of that shock the OP is limited in what shocks he can install, or have installed, on that bike. That is likely a Specialized custom tuned Fox RP23 or some variant of the F series of shock.
As far as the question; I'd say, from the looks of it, you're neglecting your shock a whole lot. Fox recommends twice-yearly seal replacement. If you shock is leaking then the seals are bad. If your LBS replaced the seals before and shortly thereafter the shock dumped its oil your LBS doesn't know how to replace seals and you need to find a new LBS.