My father's 1973 Omega Genève automatic...service or not?

Hello, and welcome to the forum!

If you intend to wear your watch and it has not been serviced in a while, consider taking your watch to an independent watchmaker who specializes in vintage watch repair rather than to an Authorized Dealer. You'll find the level of service to be a bit higher and the prices to be lower.

Ask for a full movement service from your watchmaker. Be sure to avoid any machine polishing or buffing of the gold case because the gold is quite soft. A light polish by hand is all you need.

Your watch needs a movement service because the oils that lubricate all of the small moving parts inside your watch dry out over time. A movement service consists of removing the movement from the case, checking the parts for wear, cleaning off the old crusty oils and lubricating all the small parts with fresh oils, then reassembling the movement and adjusting the timing. After that service you will have a reliable timepiece for years.