It will take approximately 20 minutes for a straight forward battery replacement and up to 60 minutes for a full battery, seal and water pressure test.
If your watch battery has stopped working and you cannot replace it immediately, we highly recommend at least removing the battery. A dead battery can leak battery acid inside your watch and cause corrosion and moisture, which can lead to rust. You then run the risk of causing greater damage to your watch.
If you are tight on time we recommend phoning ahead to book a time for your battery replacement at your local store.