At my Operator (North Sea), we have just gone in the opposite direction, going from keeping a set in the a/c to crews signing out a jacket. This has the benefit that 'Rotor High' mentioned about hygeine and also means that we can stock different size jackets for comfort. The primary reaosn, however, was the fact that we now have to fly with PSTASS and it negates going out to an aircrft only to find out that there is no air in the bottle.