evad once bubbled...
What about storing regulators with the purge depressed?
There are two schools of thought. On the one hand depressing the purge lifts the seat in the second stage off the orifice and prevents the seat from taking a set. On the other hand it leaves the entire system open to possible moisture, dust and creepy crawly things. (since the first stage seat is open as soon as the reg is removed from the tank as there is no IP pressure to close it)
So I think it depends a lot on the environment where you are storing your regs. If you live in a dry climate and are storing things in a clean dry closet depressing the purge is a good idea. If you live in a wet salt air environment and leave your stuff in the garage, I'd leave the purge closed. If the reg is adjustable, screw the adjustment all the way out to take most of the pressure off the seat.
The timing of an annual service is also something to consider. With many high performance regs it does not do you much good to have an annual service done in October and then let the seat take a set from getting pressed into the orifice all winter. If it's an adjustable reg and it was left on the minimum setting, the reg will probably still be divable but will have to be adjusted tighter and will breathe harder than it should. If the adjustment was set on max, you will either have a very hard breathing reg or be headed back to the dive shop.
A non adjustable will most likely free flow slightly after this lenght of storage and this may be able to be "fixed" at the dive shop by adjusting the orifice, but you will still end up with a reg that breathes harder than it would with a fresh seat.
In the case of an early annual service I would leave the purge depressed or alternatively (with an adjustable reg) you could remove the stop and back the adjustment screw out to the point that the seat no longer touches the orifice. Then be sure to store it in a clean, dry, dust and bug free location.