Fun coincidence! The repair store you listed there is the same store my friend went to a few days ago replace the crystal on his 70s Seiko Bellmatic. 200 pesos lang!
Evan of YoureTerrific has been preaching about this for a while now. "True" GMT movements are unnecessary if your lifestyle does not involve frequently travelling to areas in different time zones.
This is why the "Caller" GMT is in my opinion, a much more practical option for someone who does not necessarily travel, but has to communicate with people in different time zones.
TLDR:
"True GMT" - for travellers who keep moving (pilots, businessmen, people terminally on vacation)
"Caller GMT" - for keeping track of people from other time zones that you need to call (conference calls with foreign clients, relatives in another country)
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