I purchased an Omega Seamaster in 2007. According to Omega website, watches should be serviced when around 4 to 5 years old.
At the end of 2010 I sent the watch to the service centre recommended by the Omega website - The Swatch Group Belgium S.A./N.V., The Bridge, 1424 Chaussée de Mons, Bruxelles 1070
Swatch Group held the watch for over 2 months and charged me 315 Euros to service it (around 200 Euro of the cost) and repair the strap.
Within 3 weeks of the watch finally being returned, it stopped.
I returned the watch once again to Swatch Group who held on to it for another 6 weeks.
When it was finally returned to me for the second time, the date started changing at 36 hours instead of 24 hours.
Lesson - probably not safe to service your watch and certainly don't use the Swatch Group!!!

Swatch Group - www.swatchgroup.com

I bought a Tissot watch and the crown fell out. Since the watch was still under warranty it was fixed free of charge. I'm complaining because they took 6 months to repair my watch. I was learned that this is not untypical for the Swatch Group. Had I known this, I never would have purchased the watch. Tissot is owned by the Swatch Group. I have included a list of brands owned by that group. This email is not meant to speak to the quality of the watch, but the quality of the company taking your money.

Brequet
Leon Hatot
Union
Hamilton
Flick Flack
BlancPain
Omega
Balmain
Certina
Endura
Glasshutte
Rado
CK Calvin Klien
Mido
Jaquet Droz
Longines
Tissot
Swatch