Water-resistance : A hard knock might cause the watch to lose its water-resistance without you realising it. Therefore, if you plan to use your watch under water, it is essential to have the water-resistance checked at least every 12 months. If the case has to be opened for any reason, ask your Longines Agent to check the waterproof seals for the case back glass and crown, and replace them if necessary.
Automatic watches : The self-winding device in automatic watches keeps the watch wound while it is being worn. Off the wrist, it will keep going for at least 40 hours. If the watch stops, it may be rewound manually.
Quartz watches : Quartz movements are powered by a battery. Non-lithium batteries will stay charged for 12 ro 18 months, before a sudden loss of energy causes the watch to stop. Some watches are fitted with a battery end-of-life (E.O.L) indicator : when the battery is about to run down, the seconds-hand starts to jump every four seconds. When this happens, replace the battery immediately. A dead battery inside the watch might damage the movement.
Your guarantee : Always have your watch checked, serviced and repaired by a Longines Agent to maintain your guarantee.