How can you lose coolant and lubricant from a sealed system?
Like I said above, if there's a leak or if seals dry out and cause a loss of refrigerant/lubrication then fair enough, but it's impossible to lose anything from a sealed system unless there is a problem and so a "service" is a complete waste of time and money. At worst, doing unnecessary work on a good, sealed system may introduce problems that weren't there in the first place.