Clickbait title.

Because then it’ll stop running or more parts will break and the more you keep wearing it the more expensive and difficult it will be to fix it

It's important because of the oil that expires over a time there is so much friction in a watch that the certain parts of the watch get worn out. And the watch can either break or the time will be inaccurate. It always depends on the watch quality some watches can "survive" 10 years without an maintance (also called service). Either way all 2 to 4 years you should give ur watch a refreshing maintance. Same with cars they need a service too after some years.

Thanks everyone for answering. I’m asking why the clickbait, thought I might learn something new. I have other Watch service videos I would have preferred to use my time with those.

These days, it’s kind of considered a grandparent’s watch. However, opinions do vary.