We are doing a lot of commands at the moment, but I don't think this will continue for much longer. If you join today it would be at least 2 years, but unless we are getting more a/c I guess the guys who will have their command in the next 2 years will be enough to cover the retirements.
So, 2-3 years at the moment, but I think that is very optimistic for the future, but hey, its DHL and you never never know. ;-)