I always strongly advise having one’s pride Longines possession and especially 13ZNs, Weems, Lindbergh and the like being sent to and serviced by Longines in St-Imier and this for many different reasons. Here are just a few.
Firstly is is a unique occasion of establishing contact with the brand, and in this case, Longines’ heritage department is second to none in terms of responsiveness and service. Should you be as lucky to drop or fetch your own watch in St-Imier, it opens for a fantastic day out, with the visit of Longines’ wonderful museum, meeting with the heritage servicing/ restoration dept. I mean meeting on a plain and warm level, eye to eye. In doing so it is also possible to obtain a Certificate of Origin and Authenticity, a service that is uniquely free. May I remind you that Longines have the best archives in the industry, even surpassing Patek’s in being free, more detailed and much faster. A demo of LEA, Longines Electronic Archives, is really something special. You mentioned that pieces for 13ZNs are freely available in the open market. My experience is that it is only true for some limited pieces. Longines have much much more, possibly the best stock of reserve parts in the industry in comparison with any other brand. They also have an active policy of buying NOS pieces where ever they can find them in the world. I was for example very lucky that one of my 13ZN12 could be repaired, only thanks to the fact that Longines had newly bought stock from an old workshop in Madrid. A piece that is only found on 13ZN12, aka Sommatore, and therefore extremely rare.
Longines can do it all and with the greatest expertise, whether it be new hand or machine made pieces, case repair works or even expert dial restoration.
Besides, Longines are really looking after their vintage customers and they often are hosts in St-Imier or participate abroad to most friendly GTGs. I cannot think of any similar thing occurring in the the vintage world of watches.
Kind regards, Z’