How accurate are Tag Chronometers?

[alun]

I have a Tag chronometer in the Kirium Range, bought about 4 years ago in Dubai.

As long as I've owned it, I've had to add a few minutes every week.  I'd be ok with a few seconds loss a week but a few minutes just seems excessive.  I know that chronometers are not as accurate as quartz but what sort of performance should I expect?  

It's about time my watch was serviced and if there is some sort of adjustment that can be made to prevent it losing time then I'd be tempted to pay for it but I don't want to spend money for nothing.

Also, while I'm here, anyone else think the watch clasp is bit weak?  I dare not wear the watch playing sport because it unclips too easily.

Cheers for listening...  

[KTM650M]

Is not me saying it but even the Swiss Federation of Watches have something about it. The Swiss are now pushing some new testing standards - a few brands have already joined.

I have had several watches with COSC certificate and 98% of them were either very fast or very slow. Two minutes a week for me is "very"

To adjust the "speed" is  now done by machines. Any good jeweller should have the equipment to test it and set it up correctly. If in London there is a good place near Goldhawk Rd. Stn.