based on several factors;
Were the clutches in good condition when installed? oily, water wet, dry
Are the drain plugs installed so it is full of condensate/water in the compartments?
Is it parked on a dirt floor to promote poor air circulation to the open drains because you did indeed remove said drain plugs?
Are there large temperature/humidity swings where it is parked helping to promote condensation because you failed to remove the drain plugs?
Do the seals leak allowing oil to weep out of the gearbox into the clutch compartments to soak everything, thus preventing rust but creating slipping clutch which is an issue common on Gas CATs.
I know that one day the clutches will indeed stick on my D2 due to lack of winter exercise (fiber clutch on one side still, bronze clutch on other), but I do not like tying back the levers due to release bearings being put into compression along with the springs being put into compression.
DISCLAIMER! Modern Springs do not develop "Set" anymore due to Modern Advances in Technology!
(Yeah, Right!)
Most of the D4s I have seen or heard about do not seem to have Winter stuck clutches due to better design of the compartments over a D2. (My Opinion)
The D2 we used in the Pennsylvania Oil Patch was parked for up to 6 months at a time under a ragged tarp, minimal maintenance and the clutches never stuck. It was even parked for over 5 years while we used a different machine for Well Service. It was blocked up with the drain plugs out, well tarped in the woods where the sun didn't shine on it which probably helped with the temperature swings. When we went and got it, only the Magneto points needed filing to get it running. We serviced three Wells that Fall, then left it sitting on a Well location over the winter under a ragged tarp, a porcupine came along and ate all the rubber hoses off!
Jeff