Hi!
Would you mind answering a few questions?
- Is it 5 minutes + or - ?
- Has that always been the same?
- If not, do you remember if you let the watch fall to the floor, banged it against a door frame or something the like rather recently?
- Do you wear the watch daily and all day, or is it put on a dresser for prolonged times?
- Have you tried winding the watch manually?
- Does (did) it have the same problem when fully wound, manually?
First aid:
Set to correct time, then carefully wind watch manually for about 30 - 40 full turns. Continue to wear watch as you do normally and periodically check time.
Background: A watch not fully wound runs faster as it "winds down". This happens either because it doesn't get enough "movement" during the time you wear the watch (It's rare, but it does happen.) or because something is wrong with the movement itself and automatic winding mechanism.
If the watch keeps better time after manually winding it, you know that the movement itself is OK and the problem is with automatic winding. Either because something inside is broken/ not working correctly or because you're not moving around enough with your arm/wrist or have the watch sitting still for too long, literally. The latter being very typical if you don't wear your watch all day. If you only wear it to work, then put it down when home, maybe not wearing it over the weekend - your watch is running on only very few windings/ on very low "power". Kinda like barely keeping it alive, yet enough for the watch not to come to a full stop or loose an hour (or more) in very short time.
You have two options then: Buy a watch winder and put the watch on it when not used, or manually wind watch every couple of days. (If crown is the screw down type, this will lead to premature aging over a couple of years and excessive manual winding.) The watch winder, preferably one you set on with a timer, is a better option then.
If you move your arm/wrist a lot and after the initial manual winding the watch still doesn't keep time properly, something is wrong and you should have it checked by a watchmaker. The same goes if you remember you banged it into something or had it fall down.
It can be indeed as simple as calibration (highly likely if the watch has always been off by +- 5 minutes)
But I would check first if it's just about winding the watch/ it running close to "empty".
Please ask if something I wrote is not understandable/ doesn't make sense, english is not my native language.
Kind regards,
Oliver